We performed all our tests on a testbed built with the following components:
- Mainboard: ASRock Z77 Fatal1ty Professional (LGA 1155, Intel Z77 Express, BIOS version P1.20);
- Intel Core i5-3570K CPU (3.6-3.8 GHz, 4 cores, Ivy Bridge rev.E1, 22nm, 77 W, 1.05 V, LGA 1155);
- 2 x 4 GB DDR3 SDRAM Corsair Vengeance CMZ16GX3M4X1866C9R (1866 MHz, 9-10-9-27 timings, 1.5 V voltage);
- Gigabyte GV-T797OC-3GD (AMD Radeon HD 7970, Tahiti, 28 nm, 1000/5500 MHz, 384-bit GDDR5 3072 MB);
- Crucial m4 SSD (CT256M4SSD2, 256 GB, SATA 6 Gbps);
- Scythe Mugen 3 Revision B (SCMG-3100) CPU cooler;
- ARCTIC MX-2 thermal interface;
- CoolerMaster RealPower M850 PSU (RS-850-ESBA);
- Open testbed built using Antec Skeleton system case.
We used Microsoft Windows 7 Ultimate SP1 64 bit (Microsoft Windows, Version 6.1, Build 7601: Service Pack 1) operating system, Intel Chipset Software Installation Utility version 220.127.116.110, AMD Catalyst graphics card driver version 12.4.
Operational and Overclocking Specifics
Despite numerous additional features, which the developers managed to fit onto the standard ATX form-factor mainboard, ASRock Fatal1ty Z77 Professional has pretty convenient layout and we didn’t have any problems during the system assembly. When the system is on we see a startup logo with the mention of all active hot keys.
You may turn off the start-up image. In overclocked mode the processor clock frequency will be displayed correctly, which most mainboards from other manufacturers cannot do. However, as for the memory, the board will only display its size, but not the frequency.
I can admit that the initial startup and rebooting take very little time. We didn’t experience any problems in the nominal mode, besides the imperfect algorithms for the adjustment of the processor fan speed depending on the CPU temperature. The fan rotation speed adjustment feature is disabled by default on ASRock boards, which seems to be not quite the right thing. It can be easily enabled, but in this case both processor fans will be set to Level 9, which is way too high, because in this mode the rotation speed will barely ever drop. Previously when we tested ASRock mainboards, we would set it to Level 4 or Level 6 and it was more than enough. This time, however, we had to use the lowest Level 1 and 2 to ensure that the noise lowered in an acoustically comfortable manner. And it could be the end of it, but it turned out that the board was not sensitive enough to the changes in the CPU temperature. The CPU was fully utilized, but the rotation speed of its cooling fan was just starting to slowly rise. The opposite was also true: when the CPU switched to idle mode and its Vcore, as well as its frequency and temperature dropped, the processor cooling fan still continued spinning at its maximum speed.
However, these are all minor things, and the real challenges awaited us during overclocking, because we had really hard time trying to get our CPU to work at 4.6 GHz. We overclocked our test processor on ASRock Z77 Extreme4 and ASRock Z77 Extreme6 mainboards with slightly different settings in order to introduce some diversity into our tests and have the opportunity to study the mainboards’ functionality to the fullest. On one board we set Vdroop a little higher, but didn’t raise the CPU Vcore that much, and on the other we did everything the other way around. The results were identical in both cases. With ASRock Fatal1ty Z77 Professional we tried to use the same tested settings, disabled Load-Line Calibration completely and pushed the CPU Vcore to the limits, set Vdroop to its maximum and didn’t even touch the Vcore, checked out a variety of other settings combinations, but all in vain. Moreover, unlike the previously tested mainboards, which were obviously unable to overclock the processor to 4.6 GHz, we could clearly feel that we were almost there. The system passed the tests, but there was no stability in the results, the errors popped up occasionally. We couldn’t increase the CPU Vcore even a little more. In this case its temperature rapidly, almost spasmodically rose to 100 degrees or higher, so that we either terminated the tests ourselves, or the anti-overheating mechanism kicked in and the board shut down on its own. We even reinstalled the CPU cooler just in case, but it obviously wasn’t the source of the problem, because the thermal paste imprint was perfect and after we reinstalled it nothing really changed.
Since the board quickly and easily overclocked our CPU to 4.5 GHz without any stability issues, we were about to settle for this number and continue with the performance and power consumption tests, when we uncovered the stumbling stone preventing us from overclocking higher. It was the ambient room temperature! We were running the tests on an extremely hot day when the old AC unit was struggling with the heat wave from the outside and the room temperature varied between 26 and 29°C. However, as soon as we lowered the room temp to a more comfortable (for everyone) 22-25°C, all errors vanished, the CPU thermal mode got to normal, the temperature stopped snowballing and the we successfully hit 4.6 GHz increasing the memory frequency to 1867 MHz at the same time.
I have to remind you that we are always very careful about what we report in our reviews and pay particular attention to overclocking results. The so-called “screenshot overclocking” has absolutely no practical value. We, however, always achieve stable results and sometimes even take a step back from the maximum numbers to be able to provide the results that anyone can achieve. And during the series of tests of the new Z77 Express based platform we increased the frequency of our Core i5-3570K processor tested on Asus P8Z77-V Deluxe to 4.7 GHz and the system did pass all stability tests successfully. However, we perform our tests in an open testbed and it was obvious that once the same system is installed into a system case or the room temperature increases a little more, the maximum CPU temperature will be reached, which will trigger protective mechanisms and the overclocking success will backfire causing a performance drop instead of an increase. As a result, we had to stop at 4.6 GHz. Unfortunately, hot summer weather proved that the measures we took weren’t sufficient and this frequency was still too higher for our processor. So, we have to conclude that the guaranteed stability for our specific processor sample can only be achieved at 4.5 GHz.
We have to apologize that we may have misled you and set the expectations a little too high when we promised stability at 4.6 GHz CPU clock. At the same time, it is also important to pay attention to the other side of the picture. If we had stopped at 4.5 GHz clock right from the beginning, we would have found absolutely no difference in performance of the tested mainboards. Almost all of them are capable of overclocking the processor to 4.5 GHz and the 4.6 GHz bar is still unattainable for many of them. So, our mistake did a lot of good after all: it revealed the differences in the mainboards’ overclocking potential. By the way, the last mainboard we reviewed, Asus Sabertooth Z77, could only hit 4.4 GHz during our overclocking experiments, which is the lowest result of all the tested mainboards so far. But could the temperature have so negatively affected the overclocking results back then, too? Could this board have done better in more favorable thermal conditions? Possible. However, when I tested Asus Sabertooth Z77 the heat hadn’t really set in yet. I spent a lot of time trying to hit 4.5 GHz, but had to roll back to 4.4 GHz after all. However, ASRock Fatal1ty Z77 Professional passed all tests even in the peak of daytime heat, but easily maintained 4.5 GHz frequency and faced some problems only at 4.6 GHz. The difference is obvious, isn’t it?
Now I just have to remind you that we always overclock mainboards in such a way that they could be used permanently in this mode. Therefore we do not try to make our life easier by disabling any of the mainboard’s features, e.g. onboard controllers, and try to keep the CPU’s power-saving features up and running. This time we did exactly the same thing. All Intel power-saving technologies remained up and running and automatically lowered the processor Vcore as well as clock frequency multiplier in idle mode.
By the way, once all testing was completed and I was working on the ASRock Fatal1ty Z77 Professional review itself, the company released new BIOS version 1.30 update. We decided not to rerun all the benchmarks, because the board did very well anyway. Besides, we are using an Intel Core i5-3570K processor with an unlocked frequency multiplier. However, one of the major innovations in the new BIOS is the “No-K OC” function, which allows overclocking regular processors that do not have the “K” index in their model name by simply pressing one button in the BIOS.