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Testbed Configuration

We performed all our tests on a testbed built with the following components:

  • Gigabyte GA-F2A85X-UP4 rev.1.0 mainboard (Socket FM2,AMD A85X, BIOS version F3k);
  • AMD A10-5800K CPU (3.8-4.2 GHz, 4 cores, AMD Radeon HD 7660D 800 MHz, 32 nm, 100 W, 0.825-1.475 V, FM2);
  • 2 x 4 GB DDR3 SDRAM Corsair Vengeance CMZ16GX3M4X1866C9R (1866 MHz, 9-10-9-27 timings, 1.5 V voltage);
  • Crucial m4 SSD (CT256M4SSD2, 256 GB, SATA 6 Gbps);
  • Noctua NH-D14 CPU cooler;
  • ARCTIC MX-2 thermal interface;
  • Enermax NAXN ENM850EWT PSU;
  • Open testbed built using Antec Skeleton system case.

We used Microsoft Windows 8 Enterprise 64 bit (Microsoft Windows, Version 6.2, Build 9200) operating system, AMD Chipset Drivers version 12.10, AMD Catalyst graphics card driver version 12.10.

Operational and Overclocking Specifics

As usual, the system assembly on Gigabyte GA-F2A85X-UP4 went smoothly and without any problems. The installation procedure for Socket FM2 form-factor coolers remained the same as for the previous AMD processors that is why we didn’t have any issues installing our Noctua NH-D14 cooler, which is originally positioned for Socket AM2 and AM3 processors. This is yet another positive aspect unlike complete chaos that we ended up with when the retention holes layout changed on mainboards for Intel LGA 775, 1156 and 1155, 1366 and 2011 processors.

When the system is booting, we see a modest start-up image, where Gigabyte reminds us of all the supported hot keys. You may disable the start-up image, but there will be no useful info displayed on the screen. You may use the F9 key to display the basic system info, just like in the BIOS. I don’t think it is a concern, because contemporary mainboards usually boot-up so quickly that it makes practically no sense to display any startup information on the screen, since you don’t have enough time to read it anyway. Moreover, sometimes it is challenging even to catch that one moment when you can access the BIOS. Some mainboard makers even started offering software and hardware tools that allow accessing the BIOS automatically.

The new Microsoft Windows 8 Enterprise 64 bit operating system got installed fast and problem-free. Our first impression from working with the new OS is not 100% positive, but also not negative. the experience with Windows 8 installation and configuring is very similar to that with Windows 7, but a little more tricky. For example, system configuration settings can now be found not only in the traditional “Control Panel”, but also in “PC Settings” window designed as part of the new interface. The common power on and reset process now has so many stages that it turned out to be easier to create a few shortcuts on the desktop using “shutdown” command. So, if you are already using Windows 7 then there is no really good reason to switch to Windows 8. However, if you are buying a new computer system, you shouldn’t miss out on the pre-installed new OS, as eventually you will get used to it, too.

The major advantage of Socket FM2 processors is their relatively powerful integrated graphics core therefore this time we didn’t us a discrete graphics accelerator as part of our testbed. Under maximum operational load the AMD Radeon HD 7660D integrated graphics core works at 800 MHz, while in idle mode this frequency drops down to 300 MHz.

The nominal frequency of the AMD A10-5800K processor is 3.8 GHz, but in most cases it works at 4.0 GHz.

When the load is moderate, “Core Performance Boost” technology can raise the CPU clock even to 4.2 GHz.

However, if the CPU is idling, the power-saving technologies lower its voltage and the frequency drops to 1.4 GHz.

This is where direct analogy with “Intel Turbo Boost” technology comes to mind, but the operational principles of “Core Performance Boost” pose some questions and may even cause problems. For example, we failed to measure the system power consumption under peak CPU load. As usual we used LinX program for the power consumption tests and changed the number of computing threads. First we measured the system power consumption in idle mode, then in case of single-threaded load, but once we got to the maximum load of four simultaneous threads, we encountered some challenges. The power consumption usually stabilizes shortly after the load increases, and then it continues to gradually rise because of the increasing electrical resistance caused by the temperature growth. However, we detected completely the opposite behavior in our system: the power consumption would decrease with the time. It turned out that the processor dropped the frequency, sometimes even below the nominal level, to 3.4 GHz. LinX utility creates very heavy CPU load, but even with Prime95 tool the results were still the same: almost immediately after the beginning of the tests, the processor frequency dropped.

The situation when the processor is unable to function at the selected settings and lowers them is not a mystery and is attributed to over-overclocking. And it doesn’t matter if you installed these overly optimistic settings manually in an attempt to raise the CPU clock frequency, or if the processor manufacturer decided to go with unrealistically high nominal settings trying to eliminate the performance lag or cover up the issues. The result is the same in both cases: the CPU gets excessively overclocked and is unable to stay within the desired parameter range and therefore, lowers its speed. When we test overclocked systems, we dismiss these configuration options. “Screenshot overclocking”, when the overclocked processor is only capable of performing the simplest tasks, but backs out under peak operational load, has no practical value. We won’t be able to take full advantage of this mode’s potential, when needed, therefore, we immediately lower the CPU clock and Vcore to identify the parameters, which will be fully operational for a continuous period of time and not just for short-term. Unfortunately, this overly overclocked unstable state is the nominal mode for the AMD A10-5800K processor.

So, the first thing to do during CPU overclocking is to disable the “Core Performance Boost” technology to prevent it from interfering with the process, and only after that you can increase the CPU clock frequency multiplier and Vcore. However, we had to stop our AMD A10-5800K overclocking experiments almost immediately, because we were shocked by the total system power consumption levels exceeding 200 W. In fact, it wouldn’t be fair to directly compare this platform with Intel LGA 1155, because the latter finds itself in unfavorable conditions right from the start. To measure the power consumption of Intel processors we use a special version of LinX utility, which uses AVX instructions and created higher operational load. The system is equipped with a discrete graphics accelerator, a powerful Intel Core i5-3570K processor, some flagship mainboards also have an additional PCI-E hub, which also contributes quite a bit to the overall system power consumption. But even with all these factors in place, we could in the worst case see the LGA 1155 system power consumption get close to 200 W, but never exceed it. However, while overclocking AMD A10-5800K processor, which isn’t the today’ most powerful processor anyway, while using integrated graphics and a mainstream mainboard, the power consumption readings quickly exceeded the 200 W threshold.

We use all power-saving technologies not only in nominal mode but also in overclocked modes. We normally lower the mainboard’s score even if its power consumption is just a few watts above the average, and the difference here is tens of watts, while the performance levels are simply incomparable. I was so shocked that I was about to give up AMD processors for good. For example, some countries slowly discontinue regular light bulbs and switch to energy-efficient kind, which consume significantly less power. The situation here seemed to be pretty similar: if AMD processors need much more power for the same job, then maybe they should not be used for these jobs anymore. However, once I got my cool back, I decided to investigate what the contribution of individual Socket FM2 components was in case of these extreme power consumption readings.

Overclocking principles are the same for all systems. We increase the frequency and then raise the voltage in order to achieve stability. A challenge with Socket FM2 processors overclocking is that AMD failed to integrated thermal sensors into their processors that is why we chose the Vcore as our reference point and not the CPU temperature. 1.55 V is considered safe for Socket FM processors. Our tests showed that at this Vcore settings the maximum possible frequency for our specific AMD A10-5800K processor is 4.5 GHz. At the same time we increased the memory frequency and slightly adjusted its timings.

Power-saving technologies lower processor Vcore and clock frequency in idle mode.

Moreover, the frequency of the integrated graphics core was also increased from 800 to 1086 MHz.

During our test session we had absolutely no problems with the Gigabyte GA-F2A85X-UP4 mainboard. It ensured the correct nominal operation mode for the system. Only the memory with the correct frequency of 1333 MHz need a timings adjustment from 9-9-10-24 to 9-9-9-24 recorded in the modules SPD, which is no big deal. Traditionally, Gigabyte mainboard BIOS doesn’t have any tools for automatic overclocking and you can use their proprietary Easy Tune 6 utility for that. However, the “Turbo CPB” parameter in the BIOS allows you to partially correct the issues with “Core Performance Boost” technology and slightly improve the performance. If this parameter is enabled, the processor clock frequency multiplier will always rise to the maximum allowed by the Turbo Core technology for your specific model, which in our case was 42x. We also had no problems during manual processor overclocking, but overclocking of the graphics core was a little tricky. Everything seems fine, the BIOS allows adjusting the frequency in 1 MHz increments, but the major challenge is that the actual frequency of the graphics core follows completely different set of rules. For example, we started with 1000 MHz, but in reality our integrated graphics card worked at 950 MHz. We increased the frequency to 1050 MHz, but in reality it only reached 1013 MHz. It is extremely inconvenient to guess while searching for optimal parameters, and this is an issue in the mainboard BIOS. Asus mainboards can boast a much more convenient algorithm for adjustment of the integrated graphics frequency. First of all, they have several predefined overclocking profiles, and during manual configuring we are only offered to choose from those frequency values that will be used to calculate the graphics core frequency.

 

 
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