All measurements were made using a Mastech MY64 multimeter.
Search for software to detect instability
The software selected to detect instability can be roughly divided into three categories:
- Programs initially oriented as system stress tests. Included in this category LinX 0.6.4(testing was carried out in 2560 MB mode for old version Linpack, as well as in three modes, with available memory of 1024 MB, 2560 MB and 6144 MB for the latest version of Linpack, with support for FMA instructions), OCCT 4.3.2.b01(CPU test: OCCT in Large Data Set, Medium Data Set and Small Data Set modes, as well as CPU test: LINPACK in AVX mode with 90% of available memory), Prime95 v27.7 build2(in Small FFTs, In-place Large FFTs and Blend modes), CST 0.20.01a(combined test, including Matrix=5, Matrix=7 and Matrix=15 modes).
- Programs used as system performance tests, or emulating a particular load encountered in everyday PC operation. Got here Cinebench R10(test x CPU), Cinebench R11.5(CPU test), wPrime 1.55(test 1024M), POV-Ray v3.7 RC3(All CPU's test), TOC F@H Bench v.0.4.8.1(Dgromacs 2 test), 3DMark 06(test CPU1+CPU2), 3DMark Vantage(test CPU1+CPU2) and 3DMark 11(this time, separately Physics Test and separately Combined Test).
- Several CPU-dependent games. These included Colin McRae DIRT 2 Deus Ex: Human Revolution(Detroit), F1-2010(built-in performance test), Metro 2033(built-in performance test), Shogun 2 Total War (Battle of Okehazama) and The Elder Scrolls V: Skyrim(Golden Flower Estate).
Stability is defined as the state of the system in which no problems arise in its operation within 10-15 minutes of the test.
CPU instability
In this subsection of the article we will choose software, with the help of which it is easier to identify instability of the processor, with obviously stable memory frequencies and CPU_NB. The technique is relatively simple: with a fixed value of the supply voltage, select the maximum overclocking for each program and calculate a test at which the minimum frequency of stable operation will be achieved. Well, in parallel with the search for stable frequencies, you can also evaluate the behavior of the system during overclocking for a particular test. To avoid instability caused by CPU overheating, all tests were performed with a CPU supply voltage of 1.25 V.
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The "" tab has only two groups, the first of which is General(general) is responsible for the basic characteristics of memory.
- Type- type random access memory, For example, DDR, DDR2, DDR3.
- Size- memory capacity, measured in megabytes.
- Channels#- number of memory channels. Used to determine the presence of multi-channel memory access.
- DC mode- dual-channel access mode. There are chipsets that can organize dual-channel access in different ways. From simple methods This symmetric(symmetrical) - when each channel contains identical memory modules, or assymetric when memory is used of different structure and/or volume. Asymmetric mode supported Intel chipsets, beginning with 915P and NVIDIA since Nforce2.
- NB Frequency- frequency of the memory controller. Starting with AMD K10 and Intel Nehalem, the built-in memory controller received separate clocking from the processor cores. This item indicates its frequency. For systems with a memory controller located in the chipset, this item is inactive, as can be observed.
Next group - Timings. Dedicated to memory timings, which characterize the time it takes for the memory to perform a certain typical operation.
- CAS# Latency (CL)- minimum time between issuing a read command ( CAS#) and the start of data transfer (read delay).
- RAS# to CAS# Delay (tRCD)- the time required to activate a bank line, or the minimum time between sending a signal to select a line ( RAS#) and a signal to select a column ( CAS#).
- RAS# Precharge (tRP)- time required to precharge the bank (precharge). In other words, the minimum time for closing a line, after which you can activate new line jar.
- Cycle Time (tRAS)- the minimum time the line is active, that is, the minimum time between the activation of the line (its opening) and the issuing of a precharge command (the beginning of closing the line).
- Bank Cycle Time (tRC)- minimum time between activation of lines of one bank. Is a combination of timings tRAS+tRP- the minimum time the line is active and the time it closes (after which you can open a new one).
- Command Rate (CR)- the time required for the controller to decode commands and addresses. Otherwise, the minimum time between issuing two commands. With a value of 1T, the command is recognized for 1 clock cycle, with 2T - 2 clock cycles, 3T - 3 clock cycles (currently only on RD600).
- DRAM Idle Timer- the number of clock cycles after which the memory controller is forced to close and precharge open page memory if it has not been accessed.
- Total CAS# (tRDRAM)- timing used by RDRAM memory. Defines the time in clock cycles of the minimum signal propagation cycle CAS# for the RDRAM channel. Includes delay CAS# and the delay of the RDRAM channel itself - tCAC+tRDLY.
- Row to Column (tRCD)- another RDRAM timing. Defines the minimum time between opening a row and an operation on a column in that row (same as RAS# to CAS#).
If you overclock the Vishera processor, you will receive a set of different parameters in the UEFI/BIOS. Although compared to Intel platform there aren't many of them. Below we have listed the most important of them.
"Vishera" voltages
- CPU Voltage
CPU core voltage – differs from one CPU to another depending on the VID/quality of the processor. This voltage is something most overclockers should pay attention to.
- CPU-NB Voltage
CPU northbridge voltage (not to be confused with chipset voltage); This part of the CPU operates in its own frequency and voltage domain. The CPU-NB frequency determines the speed of the memory controller and L3 cache. The CPU-NB component has a fairly significant impact on the overall system performance. On high frequencies It is recommended to increase the CPU-NB voltage to improve system stability.
- CPU Voltage Offset
Most motherboards allow you to set an offset voltage that allows you to increase the voltage above the CPU VID voltage range. The offset voltage is added to the VID value and can affect overclocking in both positive and negative ways. The actual voltage is calculated as follows: CPU Voltage + Offset. Example: VID 1.350V + offset 0.100V = 1.45V actual voltage.
- NB Voltage
Chipset voltage. When overclocking by increasing the multiplier, it is not necessary to increase it.
- HT Voltage
If you want to overclock an AMD processor via the HT interface, you may need to increase this voltage.
- VDDQ
Memory voltage. Depends on the memory sticks used.
LLC/Loadline Calibration:
Prevents Vdroop effect (voltage drop under load). Unfortunately, not everyone has this setting. motherboard AMD.
Of course, our readers know everything about overclocking. In fact, many CPU and GPU reviews wouldn't be complete without looking at overclocking potential.
If you consider yourself an enthusiast, forgive us a little basic information - we'll get into the technical details soon.
What is overclocking? At its core, this term is used to describe a component that runs on more high speeds, than stated in its specifications, to increase performance. You can overclock various computer components, including the processor, memory and video card. And the level of overclocking can be completely different, from a simple increase in performance for inexpensive components to an increase in performance to an exorbitant level, which is normally unattainable for products sold in retail.
In this guide, we will focus on overclocking modern AMD processors to get the best possible performance from your chosen cooling solution.
Choosing the right components
The level of overclocking success depends very much on the system components. To begin with, you will need a processor with good overclocking potential, capable of operating at higher frequencies than the manufacturer normally specifies. AMD today sells several processors that have fairly good overclocking potential, with the "Black Edition" line of processors directly aimed at enthusiasts and overclockers due to the unlocked multiplier. We tested four processors from different families of the company to illustrate the process of overclocking each of them.
To overclock a processor, it is important that other components are also selected with this task in mind. Choosing a motherboard with an overclocking-friendly BIOS is quite critical.
We took a pair of Asus M3A78-T motherboards (790GX + 750SB), which not only provide a fairly large set of functions in the BIOS, including support for Advanced Clock Calibration (ACC), but also work perfectly with AMD utility OverDrive, which is important for getting the most out of Phenom processors.
Choosing the right memory is also important if you want to achieve maximum performance after overclocking. Where possible, we recommend installing high-performance DDR2 memory that is capable of operating at frequencies above 1066 MHz on AM2+ motherboards with 45nm or 65nm Phenom processors that support DDR2-1066.
During overclocking, frequencies and voltages increase, which leads to increased heat generation. Therefore, it is better if your system uses a proprietary power supply that provides stable voltage levels and sufficient current to cope with the increased demands of an overclocked computer. A weak or outdated power supply, loaded to capacity, can ruin all the efforts of an overclocker.
Increasing frequencies, voltages and power consumption will, of course, lead to increased heat dissipation levels, so cooling the processor and case also greatly influences the overclocking results. We didn't want to achieve any overclocking or performance records with this article, so we took rather modest coolers priced at $20-25.
This guide is intended to help those users who are less experienced in overclocking processors, so that they can enjoy the performance benefits of overclocking their Phenom II, Phenom or Athlon X2. Let's hope that our advice will help novice overclockers in this difficult but interesting task.
Terminology
Various terms that often mean the same thing can confuse or even frighten the uninitiated user. So before we go directly to step by step guide, we'll look at the most commonly encountered terms related to overclocking.
Clock speeds
CPU frequency(CPU speed, CPU frequency, CPU clock speed): the frequency at which CPU computer (CPU) executes instructions (for example, 3000 MHz or 3.0 GHz). It is this frequency that we plan to increase in order to get a performance boost.
HyperTransport channel frequency: frequency of the interface between the CPU and the northbridge (for example, 1000, 1800 or 2000 MHz). Typically the frequency is equal to (but should not exceed) the northbridge frequency.
Northbridge frequency: frequency of the northbridge chip (for example, 1800 or 2000 MHz). For AM2+ processors, increasing the northbridge frequency will lead to increased memory controller performance and L3 frequency. The frequency must be no lower than the HyperTransport channel, but it can be increased significantly higher.
Memory frequency(DRAM frequency and memory speed): The frequency, measured in megahertz (MHz), at which the memory bus operates. This may include either a physical frequency, such as 200, 333, 400, and 533 MHz, or an effective frequency, such as DDR2-400, DDR2-667, DDR2-800, or DDR2-1066.
Base or reference frequency: By default it is 200 MHz. As can be seen from AM2+ processors, other frequencies are calculated from the base using multipliers and sometimes dividers.
Frequency calculation
Before we get into the frequency calculations, it's worth mentioning that most of our guide covers overclocking AM2+ processors such as the Phenom II, Phenom, or other K10-based Athlon 7xxx models. But we also wanted to cover the early AM2 Athlon X2 processors based on the K8 core, such as the 4xxx, 5xxx and 6xxx lines. Overclocking K8 processors has some differences, which we will mention below in our article.
Below are the basic formulas for calculating the above-mentioned frequencies of AM2+ processors.
- CPU clock speed = base frequency * CPU multiplier;
- northbridge frequency = base frequency * northbridge multiplier;
- HyperTransport channel frequency = base frequency * HyperTransport multiplier;
- memory frequency = base frequency * memory multiplier.
If we want to overclock the processor (increase its clock frequency), then we need to either increase the base frequency or increase the CPU multiplier. Let's take an example: the Phenom II X4 940 processor runs with a base frequency of 200 MHz and a CPU multiplier of 15x, which gives a CPU clock speed of 3000 MHz (200 * 15 = 3000).
We can overclock this processor to 3300 MHz by increasing the multiplier to 16.5 (200 * 16.5 = 3300) or raising the base frequency to 220 (220 * 15 = 3300).
But it should be remembered that the other frequencies listed above also depend on the base frequency, so raising it to 220 MHz will also increase (overclock) the frequencies of the north bridge, the HyperTransport channel, as well as the memory frequency. On the contrary, simply increasing the CPU multiplier will only increase the CPU clock speed of AM2+ processors. Below we'll look at simple multiplier overclocking using AMD's OverDrive utility, and then head into the BIOS for more complex base clock overclocking.
Depending on the motherboard manufacturer, BIOS options for processor and northbridge frequencies sometimes use not just a multiplier, but a ratio of FID (Frequency ID) and DID (Divisor ID). In this case, the formulas will be as follows.
- CPU clock speed = base frequency * FID (multiplier)/DID (divisor);
- Northbridge frequency = base frequency * NB FID (multiplier)/NB DID (divisor).
Keeping the DID at 1 will take you to the simple multiplier formula we discussed above, meaning you can increase CPU multipliers in 0.5 increments: 8.5, 9, 9.5, 10, etc. But if you set the DID to 2 or 4, you can increase the multiplier in smaller increments. To complicate matters, the values may be specified as frequencies, such as 1800 MHz, or as multipliers, such as 9, and you may have to enter hexadecimal numbers. In any case, refer to the instructions for the motherboard or look on the Internet hexadecimal values to indicate different FIDs of the processor and northbridge.
There are other exceptions, for example, it may not be possible to set multipliers. Thus, in some cases, the memory frequency is set directly in the BIOS: DDR2-400, DDR2-533, DDR2-800 or DDR2-1066 instead of selecting a memory multiplier or divider. In addition, the frequencies of the northbridge and HyperTransport channel can also be set directly, and not through a multiplier. In general, we don't recommend worrying too much about these differences, but we recommend returning to this part of the article if the need arises.
Test hardware and BIOS settings
Processors
- AMD Phenom II X4 940 Black Edition (45 nm, Quad-Core, Deneb, AM2+)
- AMD Phenom X4 9950 Black Edition (65 nm, Quad-Core, Agena, AM2+)
- AMD Athlon X2 7750 Black Edition (65 nm, Dual-Core, Kuma, AM2+)
- AMD Athlon 64 X2 5400+ Black Edition (65 nm, Dual Core, Brisbane, AM2)
Memory
- 4 GB (2*2 GB) Patriot PC2-6400 (4-4-4-12)
- 4 GB (2*2 GB) G.Skill Pi Black PC2-6400 (4-4-4-12)
Video cards
- AMD Radeon HD 4870 X2
- AMD Radeon HD 4850
Cooler
- Arctic Cooling Freezer 64 Pro
- Xigmatek HDT-S963
Motherboard
- Asus M3A78-T (790GX+750SB)
power unit
- Antec NeoPower 650 W
- Antec True Power Trio 650W
Useful utilities.
- AMD OverDrive: overclocking utility;
- CPU-Z: system information utility;
- Prime95: stability test;
- Memtest86: memory test (bootable CD).
Hardware monitoring: Hardware Monitor, Core Temp, Asus Probe II, other utilities included with the motherboard.
Performance testing: W Prime, Super Pi Mod, Cinebench, 3DMark 2006 CPU test, 3DMark Vantage CPU test
- Manually configure Memory Timings;
- Plan Windows power supply: High Performance.
Remember that you are exceeding the manufacturer's specifications. Overclocking is done at your own risk. Most hardware manufacturers, including AMD, do not provide a warranty against damage caused by overclocking, even if you use AMD's utility. THG.ru or the author are not responsible for damage that may occur during overclocking.
Introducing AMD OverDrive
AMD OverDrive - powerful utility"all-in-one" for overclocking, monitoring and testing, designed for motherboards based on the AMD 700 line of chipsets. Many overclockers do not like to use a software utility under the operating system, so they prefer to change the values directly in the BIOS. I also usually avoid utilities that come with motherboards. But after testing the latest versions of the AMD OverDrive utility on our systems, it became clear that the utility is quite valuable.
We'll start by looking at the AMD OverDrive utility menu, highlighting interesting opportunities, as well as unlocking advanced features that we will need. After launching the OverDrive utility, you are greeted with a warning message, clearly stating that you are using the utility at your own risk.
When you agree, pressing the "OK" key will take you to the "Basic System Information" tab, which displays information about the CPU and memory.
The "Diagram" tab displays a chipset diagram. If you click on a component, more will be displayed detailed information about him.
The "Status Monitor" tab is very useful during overclocking, as it allows you to monitor the processor clock speed, multiplier, voltage, temperature and load level.
If you click on the "Performance Control" tab in the "Novice" mode, you will get a simple engine that allows you to change the frequency PCI Express(PCIe).
To unlock advanced frequency settings, go to the "Preference/Settings" tab and select "Advanced Mode".
After selecting the "Advanced" mode, the "Novice" tab was replaced by the "Clock/Voltage" tab for overclocking.
The "Memory" tab displays a lot of information about memory and allows you to configure delays.
There's even a built-in test to quickly evaluate performance and compare it with previous values.
The utility also contains tests that load the system to check the stability of operation.
The last tab "Auto Clock" allows you to perform automatic overclocking. It takes a lot of time, and all the excitement is lost, so we didn’t experiment with this function.
Now that you're familiar with AMD's OverDrive utility and have set it to Advanced mode, let's move on to overclocking.
Overclocking via multiplier
WITH motherboard On the 790GX chipset and the Black Edition processors we used, overclocking using AMD OverDrive is quite easy. If your processor is not a Black Edition processor, you will not be able to increase the multiplier.
Let's take a look at the stock operating mode of our Phenom II X4 940 processor. The motherboard base frequency varies from 200.5 to 200.6 MHz for our system, which gives a core frequency between 3007 and 3008 MHz.
It is useful to run some performance tests at the standard clock frequency, so that you can then compare the results of an overclocked system with them (you can use the tests and utilities we suggested above). Performance tests allow you to measure performance gains and losses after changing settings.
To overclock a Black Edition processor, check the "Select All Cores" checkbox on the "Clock/Voltage" tab, then start increasing the CPU multiplier in small steps. By the way, if you don’t check this box, you can overclock the processor cores individually. As you overclock, be sure to keep an eye on temperatures and constantly run stability tests. In addition, we recommend making notes regarding each change where you describe the results.
Since we were expecting a solid boost from our Deneb processor, we skipped the 15.5x multiplier and went straight to the 16x multiplier, which gave the CPU core clock at 3200 MHz. With a base frequency of 200 MHz, each increase in the multiplier by 1 gives an increase in clock frequency of 200 MHz, and an increase in the multiplier by 0.5 - 100 MHz, respectively. We performed stress tests after overclocking using the AOD stability test and the Small FFT Prime95 test.
After running Prime 95 stress tests for 15 minutes without a single error, we decided to further increase the multiplier. Accordingly, the next multiplier of 16.5 gave a frequency of 3300 MHz. And at this core frequency, our Phenom II passed through stability tests without any problems.
A multiplier of 17 gives a clock speed of 3400 MHz, and again stability tests were completed without a single error.
At 3.5 GHz (17.5*200) we successfully completed a one-hour stability test under AOD, but after about eight minutes in the heavier Prime95 application we got " blue screen" and the system rebooted. We were able to run all the performance tests at these settings without crashing, but we still wanted our system to go through the 30-60 minute Prime95 test without crashing. Therefore, the maximum overclock level for our processor at stock voltage is 1.35 V is between 3.4 and 3.5 GHz. If you don't want to increase the voltage, you can stop there. Or you can try to find the maximum stable CPU frequency at a given voltage, increasing the base frequency in steps of one megahertz, which for a multiplier of 17 will give 17 MHz at each step.
If you don’t mind raising the voltage, then it is better to do this in small increments of 0.025-0.05 V, while you need to monitor the temperatures. Our CPU temperatures remained low, and we began to gradually increase the CPU voltage, with a small increase to 1.375 V resulting in Prime95 tests running at 3.5 GHz completely stable.
Stable operation with a multiplier of 18 at 3.6 GHz required a voltage of 1,400 V. To maintain stability at 3.7 GHz, a voltage of 1.4875 V was required, which is more than the AOD allows to set by default. Not every system will be able to provide sufficient cooling at this voltage. To increase the default AOD limit, you should edit the AOD .xml parameters file in Notepad, increasing the limit to 1.55 V.
We had to raise the voltage to 1,500 V to get the system to work stably in the 3.8 GHz tests with a multiplier of 18, but even raising it to 1.55 V did not lead to stable operation of the Prime95 stress test. The core temperature during Prime95 tests was somewhere in the region of 55 degrees Celsius, meaning we hardly needed better cooling.
We rolled back to the 3.7 GHz overclock, and the Prime95 test ran successfully for an hour, meaning system stability was verified. We then started increasing the base frequency in 1 MHz increments, with the maximum overclock level being 3765 MHz (203*18.5).
It is important to remember that the frequencies that can be obtained through overclocking, as well as the voltage values for this, change from one processor sample to another, so in your case everything may be different. It is important to increase frequencies and voltages in small increments while performing stability tests and monitoring temperatures throughout the process. With these CPU models, increasing the voltage does not always help, and processors may even become unstable if the voltage is increased too much. Sometimes for better overclocking It is enough to simply strengthen the cooling system. For optimal results, we recommend keeping the CPU core temperature under load below 50 degrees Celsius.
Although we were unable to increase the processor frequency above 3765 MHz, there are still ways to further improve system performance. Increasing the frequency of the northbridge, for example, can have a significant impact on application performance, since it increases the speed of the memory controller and L3 cache. The northbridge multiplier cannot be changed from the AOD utility, but this can be done in the BIOS.
The only way to increase the northbridge clock speed under AOD without rebooting is to experiment with the CPU clock speed with a low multiplier and a high base frequency. However, this will increase both the HyperTransport speed and the memory frequency. We'll look at this issue in more detail in our guide, but for now let me present the results of overclocking three other Black Edition processors.
The other two AM2+ processors are overclocked in exactly the same way as the Phenom II, with the exception of one more step - enabling Advanced Clock Calibration (ACC). The ACC function is only available on motherboards with AMD SB750 Southbridge, such as our ASUS model with the 790GX chipset. The ACC feature can be enabled in both AOD and BIOS, but both require a reboot.
For 45nm Phenom II processors, it is better to disable ACC as AMD states that this function already present in the Phenom II crystal. But with 65nm K10 Phenom and Athlon processors, it is better to set ACC to Auto, +2% or +4%, which can increase the maximum achievable processor frequency.
Standard frequencies.
Maximum multiplier
Maximum overclocking
The screenshots above show the overclocking of our Phenom X4 9950 at the stock frequency of 2.6 GHz with a 13x multiplier and a processor voltage of 1.25 V. The memory frequency is crossed out because it was set to DDR2-1066, and not to the DDR2-800 mode that we used for overclocking. The multiplier was increased to 15x, giving a 400 MHz overclock at stock voltage. The voltage was increased to 1.45V, then we tried ACC settings on Auto, +2%, and +4%, but the Prime95 could only last 12-15 minutes. Interestingly, with ACC in Auto mode, a 16.5x multiplier and a voltage of 1.425V, we were able to increase the base frequency to 208MHz, which gave a higher stable overclock.
Standard frequencies
Maximum overclocking without increasing voltage
Maximum overclocking without using ACC
Maximum overclocking
Our Athlon X2 7750 operates at a standard frequency of 2700 MHz and a voltage of 1.325 V. Without increasing the voltage, we were able to increase the multiplier to 16x, which gave a stable operating frequency of 3200 MHz. The system was also stable at 3300 MHz when we increased the voltage slightly to 1.35 V. With ACC disabled, we increased the processor voltage to 1.45 V in 0.025 V increments, but the system was not able to operate stably at the 17x multiplier. It crashed even before stress testing. Setting ACC for all cores to +2% allowed us to achieve an hour of stable Prime95 operation at 1.425 V. The processor did not respond very well to voltage increases above 1.425 V, so we were able to get a maximum stable frequency of 3417 MHz.
The benefits of enabling ACC, as well as the results of overclocking in general, vary significantly from one processor to another. However, it’s still nice to have such an option at your disposal, and you can spend time fine-tuning the overclocking of each core. We didn't see any significant overclocking gains from enabling ACC on either processor, but we still recommend checking out our 790GX review where we took a closer look at ACC and where it made a more significant impact on the Phenom X4 9850's overclocking potential.
BIOS options
Our maternal Asus board M3A78-T has been flashed latest version A BIOS that contains support for new CPUs and also provides the best chance of successful overclocking.
First you need to log in Motherboard BIOS board (usually done by pressing the "Delete" key during the POST boot screen). Check your motherboard's manual to see how you can clear the CMOS (usually using a jumper) if the system fails the POST boot test. Remember that if this happens, all previously made changes such as time/date, GPU off, boot order, etc. will be lost. If you're new to BIOS setup, pay close attention to the changes you make and write down the initial settings if you can't remember them later.
Simply navigating the BIOS menu is completely safe, so if you're new to overclocking, don't be afraid. But make sure you exit the BIOS without saving any changes you've made if you think you might accidentally mess something up. This is usually done by pressing the "Esc" key or the corresponding menu option.
Let's dive into BIOS Asus M3A78-T as an example. BIOS menu vary from one motherboard to another (and from one manufacturer to another), so use the manual to find the appropriate options in your model's BIOS. Also, remember that the available options vary greatly depending on your motherboard model and chipset.
In the main menu (Main) you can set the time and date, and the connected drives are also displayed there. If a menu item has a blue triangle on the left, you can go to a submenu. The "System Information" item, for example, allows you to view the BIOS version and date, processor brand, frequency and amount of installed RAM.
The "Advanced" menu consists of several nested submenus. The "CPU Configuration" item displays information about the processor and contains a number of options, some of which are best disabled for overclocking.
You will probably spend most of your time in the "Advanced" menu item "JumperFree Configuration". Manual setting of important settings is ensured by switching the “AI Overclocking” item to the “Manual” mode. On other motherboards, these options will probably be located in a different menu.
Now we have access to the necessary multipliers that can be changed. Please note that in the BIOS the CPU multiplier changes in steps of 0.5, and the northbridge multiplier in steps of 1. And the HT channel frequency is indicated directly, and not through the multiplier. These options vary significantly between different motherboards; for some models they can be set via FID and DID, as we mentioned above.
In the "DRAM Timing Configuration" item you can set the memory frequency, be it DDR2-400, DDR2-533, DDR2-667, DDR2-800 or DDR2-1066, as shown in the photo. In this BIOS version you won't need to set the memory multiplier/divider. In the "DRAM Timing Mode" item you can set delays, either automatically or manually. Reducing latency can improve performance. However, if you don’t have completely stable memory latency values at hand different frequencies, then during overclocking it is very reasonable to increase the delays CL, tRDC, tRP, tRAS, tRC and CR. Additionally, you can get higher memory frequencies if you increase tRFC latencies to very high values such as 127.5 or 135.
Later, all the "relaxed" delays can be returned back to squeeze out more performance. Reducing one latency per system run is time-consuming, but worth the effort to get maximum performance while maintaining stability. When your memory runs outside of specifications, run a stability test with utilities such as the Memtest86 boot CD, as unstable work memory may lead to data corruption, which is undesirable. With all that said, it is quite safe to give the motherboard the ability to adjust the latencies on its own (usually this will set fairly “relaxed” latencies) and focus on overclocking the CPU.
Advanced overclocking
In this case, the adjective “advanced” is not very appropriate, since, unlike the methods discussed above, we will present here overclocking through the BIOS by increasing the base frequency. The success of such an overclock depends on how well the components in your system can overclock, and to find the capabilities of each of them, we will go through them one by one. In principle, no one forces you to follow all the steps given, but finding the maximum for each component can ultimately lead to higher overclocking, since you will understand why you are running into one or another limit.
As we said above, some overclockers prefer direct overclocking through the BIOS, while others use AOD to save testing time by not having to reboot every time. The settings can then be manually entered into the BIOS and try to improve them even further. In principle, you can choose any method, since each has its own advantages and disadvantages.
Again, it would be a good idea to disable the Cool"n"Quiet and C1E, Spread Spectrum and automatic systems fan controls that reduce its rotation speed. We also turned off the "CPU Tweak" and "Virtualization" options for part of our tests, but did not find a noticeable effect on any of the processors. These features can be enabled later if required and you can check if they impact system performance or the stability of your overclock.
Finding the maximum base clock speed
Now we'll move on to the techniques that owners of non-Black Edition processors will have to follow to overclock them (they cannot increase the multiplier). Our first step is to find the maximum base frequency (bus frequency) at which the processor and motherboard can operate. You will quickly notice all the confusion in the naming of the various frequencies and multipliers, as we already mentioned above. For example, the reference clock in AOD is called "Bus Speed" in CPU-Z and "FSB Frequency" in this BIOS.
If you plan to overclock only through the BIOS, then you should lower the CPU multiplier, northbridge multiplier, HyperTransport multiplier and memory multiplier. In our BIOS, lowering the Northbridge multiplier automatically reduces the available HyperTransport channel frequencies to or below the resulting Northbridge frequency. The CPU multiplier can be left as standard and then lowered in AOD, which makes it possible to further increase the CPU frequency without rebooting.
For our Phenom X4 9950 processor, we selected an 8x multiplier in the AOD utility, since even a 300 MHz base frequency with such a multiplier will be lower than the standard CPU frequency. We then raised the base frequency from 200 MHz to 220 MHz, and then increased it in 10 MHz steps up to 260 MHz. We then moved to 5 MHz steps and increased the frequency to a maximum of 290 MHz. In principle, it is unlikely to increase this frequency to the limit of stability, so we could easily stop at 275 MHz, since it is unlikely that the northbridge will be able to operate at such a high frequency. Since we were overclocking the base clock in the AOD, we ran AOD stability tests for a few minutes to ensure the system was stable. If we did the same thing in the BIOS, simply being able to boot into Windows would probably be a good enough test, and then we'd run final stability tests at a high base clock to make sure.
Finding the maximum CPU frequency
Since we already reduced the multiplier in AOD, we know the maximum CPU multiplier and now we already know the maximum base frequency we can use. With the Black Edition processor we can experiment with any combination within these limits to find the maximum value of other frequencies, such as the northbridge frequency, the HyperTransport channel frequency and the memory frequency. On this moment We will continue the overclocking tests as if the CPU multiplier was locked at 13x. We will look for the maximum CPU frequency by increasing the bus frequency by 5 MHz at a time.
Whether overclocking via BIOS or via AOD, we can always go back to the base clock of 200 MHz and set the multiplier back to 13x, which will give a stock clock speed of 2600 MHz. By the way, the north bridge multiplier will still remain 4, which gives a frequency of 800 MHz, the HyperTransport channel will operate at 800 MHz, and the memory will operate at 200 MHz (DDR2-400). We will follow the same procedure of increasing the base frequency in small increments, performing stability tests each time. If necessary, we will increase the CPU voltage until we reach the maximum CPU frequency (by enabling ACC in parallel).
Maximum performance gain
Having found the maximum CPU frequency of our AMD processors, we have taken a significant step towards increasing system performance. But processor frequency is only part of overclocking. To get maximum performance, you can work on other frequencies. If you increase the voltage of the north bridge (NB VID in AMD OverDrive), then its frequency can be increased to 2400-2600 MHz and higher, and you will increase the speed of the memory controller and L3 cache. Increasing the frequency and reducing RAM latency can also have a positive effect on performance. Even the high-end DDR2-800 memory we used can be overclocked above 1066 MHz, increasing voltage and possibly reducing latency. HyperTransport channel frequency generally does not affect performance above 2000 MHz and can easily lead to instability, but it can also be overclocked. The PCIe frequency can also be slightly overclocked to around 110 MHz, which can also provide a potential performance boost.
As all mentioned frequencies slowly rise, stability and performance tests should be carried out. Setting up different parameters is a lengthy process and may be beyond the scope of our guide. But overclocking is always interesting, especially since you will get a significant performance boost.
Conclusion
Let's hope that all our readers who want to overclock an AMD processor now have a sufficient amount of information on hand. Now you can start overclocking using the AMD OverDrive utility or other methods. Remember that the results and exact sequence of actions vary from one system to another, so you should not blindly copy our settings. Use this manual only as a guide to help you discover the potential and limitations of your system for yourself. Take your time, don't increase your pitch, monitor temperatures, perform stability tests, and increase the voltage a little if necessary. Always carefully probe the safe overclocking limit, since a sharp increase in frequency and voltage blindly is not only a wrong approach for successful overclocking, but it can also damage your hardware.
The last piece of advice: each motherboard model has its own characteristics, so it doesn’t hurt to familiarize yourself with the experiences of other owners of the same board before overclocking. Advice from experienced users and enthusiasts who have tried it this model motherboard in operation, I will help you avoid pitfalls.
Addition
We tested another copy of the AMD Phenom II X4 940 Black Edition processor, provided by the Russian representative office of AMD. It ran successfully at 3.6 GHz when we increased the supply voltage to 1.488 V (CPUZ data). It looks like 3.6GHz is the threshold for most CPUs when air cooled. We successfully overclocked the memory controller to 2.2 GHz.
Review and study of the overclocking potential of the AMD Phenom II X6 1075T processor
- Introduction
- Specifications
- Packaging and appearance
- Test configuration
- AMD Turbo Core Technology
- Memory overclocking
- Bus overclocking (HTT)
- Overclocking using liquid nitrogen
- Energy consumption measurement
- Conclusion
Introduction
Within a few months after the first 6-core processors entered the market AMD Phenom II X6 on the core Thuban, there were only two models left in the line of these processors - the older 1090T Black Edition and junior 1055T. It was also recently released new flagship Phenom II X6 1100T Black Edition, but this time we will not talk about it, but about the Phenom II X6 1075T processor released last fall, which took an intermediate position between the 1090T Black Edition and 1055T.
Core processor performance level Thuban has long been known and well studied. In this regard, the release of the new model did not bring any changes. The nominal frequency of the processor (and therefore its performance in normal mode) is in the middle between the two models closest to it and differs from them only in the multiplier. Therefore, we will not dwell on this issue in detail, but will only test the processor for overclocking (including extreme) and compare the results of measuring the energy consumption of systems based on 6-core AMD and Intel processors.
For testing, we used a processor instance released in the 23rd week of 2010, that is, in early June:
Specifications
Processor Specifications AMD Phenom II X6 tabulated:
*Frequencies and multiplier values for active technology are indicated in parentheses AMD Turbo Core
The Phenom II X6 1075T processor actually turned out to be not so much an addition to AMD's 6-core line, but rather a replacement for the Phenom II X6 1055T. With their price being the same at $199, there is now no reason to buy the 1055T instead of the 1075T.
All processors have the same characteristics (stepping, TDP, cache size, etc.) and differ only in the nominal frequency and multiplier. Plus, the two older processors are distinguished by the presence of a free multiplier for increasing.
Test configuration
An open stand with the following configuration was used for testing:
- Processor: AMD Phenom II X6 1075T E0 (Thuban);
- Motherboard: Asus Crosshair IV Formula, AMD 890FX + SB850, BIOS 1102;
- Memory: G.Skill Perfect Storm F3-16000CL7T-6GBPS 7-8-7-20 1.65V 3x2048Mb (only two memory modules were used);
- Video cards: Palit GeForce 7300GT Sonic, 256 MB GDDR3, PCI-E;
- Hard drive: Western Digital WD1500HLFS (Velociraptor), 150 Gb;
- Power supply: Topower PowerTrain TOP-1000P9 U14 1000W;
- Thermal paste: Arctic Silver Ceramique;
- CPU cooling: Glacial Tech F101 PWM.
Software:
- OS Windows 7 Ultimate build 7600 x86;
- DirectX June 2010 Redistributable;
- NVIDIA ForceWare v258.96;
- Asus TurboV EVO v1.02.23;
- CPU-Z v1.55;
- Core Temp v0.99.7;
- LAVALYS Everest Ultimate v5.50.2183 Beta;
- LinX 0.6.4.
AMD Turbo Core Technology
The processor, like other models based on the Thuban core, supports AMD Turbo Core automatic overclocking technology, as indicated by the last letter “T” in its name. The principle of operation of AMD Turbo Core is generally similar to the technology Turbo Boost for processors manufactured by Intel and is based on controlling the frequency of individual cores and processor voltage, depending on the level of load on them. One of the main differences from Intel processors is that AMD Turbo Core increases the multipliers on half of the loaded cores while simultaneously decreasing the multipliers on the remaining unused ones. That is, to activate AMD Turbo Core, it is necessary that no more than half of the processor cores are loaded, that is, no more than three in the case of a 6-core Thuban core and no more than two for 4-core Zosma.
To support AMD Turbo Core technology, just update the motherboard BIOS. After which an option will appear that allows you to disable this technology if desired. However, you can also use the utility for this AMD Overdrive.
When activating AMD Turbo Core processor AMD Phenom II X6 1075T automatically increases the multiplier on three loaded cores from x15 to x17.5. With a nominal HTT operating frequency of 200 MHz, this gives a frequency increase of 500 MHz (from 3000 to 3500). At the same time, the multipliers on the cores that remain free are reduced to x4, which gives their final frequency of 800 MHz, if the processor is operating in normal mode. Without load (provided that power-saving technologies are disabled), as well as with a simultaneous load of more than four or more cores, the multipliers of all cores remain at the nominal value of x15.
Another important difference AMD Turbo Core from Intel Turbo Boost- the inability to fix an increased multiplier for constant use using BIOS tools, regardless of the load. Motherboards for Socket platforms 1366 and Socket 1156 learned to do this a long time ago, including budget models, although not all. And for boards for AMD processors, including models on the latest flagship AMD chipset 890FX, there is no such option yet. Even disabling some kernels in the BIOS does not help. Unfortunately, this nullifies the practical benefit of AMD Turbo Core for overclockers who are able to independently configure all the parameters for overclocking the processor. When the processor operates at frequencies close to the limit of its stable operation, spontaneous changes in multipliers leading to frequency jumps of several hundred megahertz are simply unacceptable. The standard multiplier of the AMD Phenom II X6 1075T (and even the youngest in the AMD Phenom II X6 1055T line), available without activating the AMD Turbo Core, is quite enough for normal non-extreme overclocking in air and using water cooling to frequencies in the region of 4000-4200 MHz. Therefore, when overclocking processors based on the Thuban core, it is better to disable AMD Turbo Core technology.
As for extreme overclocking, AMD Turbo Core may be useful here, but only if the motherboard is not capable of operating at high HTT frequencies, and the processor does not belong to the Black Edition series, that is, it has a multiplier blocked for increase. In this case, the only way to increase the frequency is to increase the multiplier above the standard one using AMD Turbo Core. Moreover, this can be useful not only in single-threaded benchmarks, but also in all others, for which only three cores are enough to get a good result, if you link to them (for example, using the task manager). But here you need to take into account that you will not be able to manually control the multipliers on the cores. And again, sharp jumps in frequencies and voltages can prevent successful overclocking, and in order to get the result in CPU-Z (or any screenshot with the frequencies at which any benchmark was actually passed) you will have to create a background load in parallel on at least one core. In other words, it is impossible to obtain effective results during extreme overclocking under AMD Turbo Core operating conditions.
Air-cooled overclocking and temperature control
A cooler was used to cool the processor Glacial Tech F101 PWM. The room temperature during testing was +21°C.
Standard voltages may differ slightly for different processors. In our case, the default Vcore was 1.325 V, and the voltage of the built-in memory controller ( CPU_NB Voltage) - 1.1625 V.
At the nominal frequency the processor warmed up very little. The temperature was +34°C at rest and +41°C under load:
Due to the peculiarities of the used motherboard, which overestimates the HTT bus frequency, the nominal frequency was also set with a slight overestimation to 3011 MHz.
As it turned out, BIOS 1102 For Asus Crosshair IV Formula has one unpleasant feature: Vcore overestimation under load after enabling the function Loadline Calibration. And the more cores the processor used, the higher the level of overestimation. At standard voltage this is not very noticeable; the overestimation was about 0.1 V (i.e. 1.332 V at rest increased to 1.344 V under load). But already when setting 1.45 V on 6-core processors, it increases by 0.5V (that is, up to 1.50 V), which is not small at all. And if Loadline Calibration is not turned on, then significant voltage drops begin, which is even worse than overestimation.
Overclocking an air-cooled processor is limited by frequency
4043 MHz:
Despite a decent temperature margin (+35°C at rest and +49°C under load), increasing the voltage above 1.50 V under load did not lead to a further improvement in the overclocking potential.
AMD Turbo Core technology has been disabled since the stock x15 multiplier is more than enough for air-cooled overclocking. On the contrary, the multiplier even had to be reduced to x13 in order to select the most optimal operating mode for the memory and CPU_NB, in which their frequencies would also be close to the maximum.
The maximum frequency recorded by the CPU-Z program on air cooling was 4500 MHz with voltage 1.476 V:
It was obtained on the second core (core1), which turns out to be the best overclocking on all AMD processors we tested. For the remaining cores the results were as follows:
- Core0: 4304 MHz;
- Core2: 4439 MHz;
- Core3: 4424 MHz.
Overclocking the built-in memory controller (CPU_NB)
The memory controller fell just short of three gigahertz. After setting the CPU_NB voltage equal to 1.35 V in the BIOS, the frequency was obtained 2980 MHz. At the same time, monitoring in the LAVALYS Everest program showed the voltage as 1.36 V at rest and 1.38 V under load.
The maximum CPU_NB frequency at which it was possible to take a screenshot was at the level 3200 MHz:
Memory overclocking
After unsuccessful attempts in the past to get memory to work on the AMD platform at 2000 MHz with the Phenom II X6 1090T processor, there was hope that another instance of the Thuban core processor could help with this, but, unfortunately 1900 MHz This is all that the built-in memory controller of our Phenom II X6 1075T sample was capable of:
This is only slightly better than the results of the same memory and on the same motherboard with core processors Deneb.
The maximum “screenshot” memory frequency in CPU-Z also fell short of two gigahertz and amounted to 1966 MHz:
Bus overclocking (HTT)
But with overclocking the HTT frequency, everything was fine with this processor. Download option operating system up to a frequency of 376 MHz and further overclocking from Windows using the program Asus TurboV EVO before 422 MHz:
The high nominal frequency and voltage of AMD processors also leads to higher power consumption when operating in normal mode, but as soon as you overclock an Intel processor with a voltage of 1.40 V or higher, it immediately outperforms its rival in this indicator.
Conclusion
In conclusion, let's summarize the advantages and disadvantages of the processor AMD Phemon II X6 1075T:
[+] Along with AMD, the Phenom II X6 1055T is the cheapest 6-core processor currently available. Many times cheaper than all 6-core Intel processors, and even cheaper than many 4-core ones.
[+] Very low operating temperatures, even when overclocked with increasing voltage;
[+] The standard multiplier is more than enough for overclocking using air and liquid cooling systems. And if you use a good motherboard, it will most likely be enough for extreme overclocking;
[+] Support for proprietary AMD Turbo Core technology;
[-] Multiplier locked for increase;
[-] The integrated memory controller is still unable to work with high-frequency kits whose frequency exceeds 2000 MHz;
[-] Overclocking potential under extreme overclocking may be lower than that of the older 1090T and 1100T models.
We would like to express our gratitude to our partner, AMD, for providing the Phenom II X6 1075T processor for testing.
We suggest discussing this material in a special thread of ours.
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