We carried out our tests on a testbed that included the following components:
- Asus P8Z77-M rev. 1.01 mainboard (LGA 1155, Intel Z77 Express, BIOS version 1908);
- Gigabyte GA-Z77M-D3H rev. 1.1 (LGA1155, Intel Z77 Express, BIOS version F13);
- 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);
- Intel HD Graphics 4000 integrated graphics core;
- Crucial m4 SSD (CT256M4SSD2, 256 GB, SATA 6 Gbps);
- Scythe Mugen 3 Revision B (SCMG-3100) CPU cooler;
- ARCTIC MX-2 thermal interface;
- Enhance EPS-1280GA 800 W 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, Intel Chipset Device Software driver package version 188.8.131.527, Intel HD Graphics Driver version 184.108.40.206.3071 (220.127.116.1171).
Operational and Overclocking Specifics
We had no problems assembling our testbed around the ASUS P8Z77-M and Gigabyte GA-Z77M-D3H, mostly because we had decided not to use any expansion cards, including graphics cards. However, we can tell you that even large CPU coolers, like our Scythe Mugen 3, wouldn’t prevent you from installing a discrete graphics card on either of these mainboards.
The ASUS P8Z77-M doesn’t show any hotkey prompts on its startup picture, except for the well-known Del key. If you disable the startup picture in the mainboard’s BIOS (or if you guess without any prompts that it can be turned off by pressing Tab), you will get a lot of information from the mainboard about its model name, BIOS version, CPU model name, and memory amount and frequency. However, instead of the actual CPU clock rate the mainboard will report its specified clock rate, even without considering the Turbo technology, which is turned on by default.
Well, today’s mainboards start up so fast that it’s hard not only to read what they output on the screen but even to press the button to enter their BIOS. That’s why you may want to use the ASUS Boot Setting utility to automatically load the BIOS interface from Windows (we mentioned it in our ASUS P8Z77-V LK review). As for us, we just turned off the Fast Boost option in the mainboard’s BIOS (it’s in the Boot section) for the duration of our tests.
All of the power-saving technologies available in Intel CPUs are enabled on the P8Z77-M by default and work correctly. Additionally, you can turn on EPU Power Saving Mode using a corresponding BIOS option. The CPU worked in full compliance with its official specs, and we could easily accelerate it by enabling ASUS MultiCore Enhancement, which increased the CPU’s frequency multiplier to the maximum level as normally permitted by the Intel Turbo Boost technology for single-threaded load only. To reach higher performance, you can also use the OC Tuner option, which overclocks the CPU automatically. In our case, the base clock rate was increased to 102 MHz and the CPU frequency multiplier, to x41. The resulting CPU clock rate was 4.2 GHz. The integrated graphics core and system memory were also overclocked to 1300 and 1900 MHz, respectively.
It’s good that all of the key system components are covered by the automatic overclocking technology, but we tried to find optimal settings manually. Unfortunately, the mainboard couldn’t make our CPU stable at its maximum clock rate of 4.6 GHz, so we limited ourselves to 4.5 GHz. We also increased the memory frequency to 1866 MHz and adjusted memory timings as was necessary.
We want to remind you that we prefer “sustained” overclocking, which means that the overclocked system can be used continuously. We don’t disable any features or controllers. We keep Intel’s power-saving technologies up and running so they lower the CPU’s frequency multiplier and voltage, disable unused CPU subunits and switch the CPU into power-saving modes at low loads.
As opposed to its opponent, the Gigabyte GA-Z77M-D3H shows a startup picture in the bottom of which you can see a list of active hotkeys. Pressing the Del key will lead you to the mainboard's BIOS. F9 will show a window with system information (the same key displays the same window if pressed in the BIOS, too). F12 opens up a menu to choose a device to boot from. The End key can be pressed to launch the integrated firmware update tool Q-Flash.
There’s no Tab key listed here which is usually used to remove the startup picture. You can disable the latter in the BIOS, but the fact is, unlike most mainboards from other brands, Gigabyte ones do not output any boot-related information on the screen. The only thing you can see is an AMI logo since the BIOS is based on AMI’s code.
Like its opponent, the mainboard selected standard settings for the CPU and memory by default, making all of Intel’s power-saving technologies functional. As for the integrated graphics core, its frequency would be dropped to 350 MHz at low loads, as is normal for the Intel HD Graphics 4000, but would increase to 1200 instead of 1150 MHz at high loads. You can't even spot this in the BIOS since the Processor Graphics Clock parameter reports the standard 1150 MHz, which is not true.
The difference isn’t large, yet it turns out that the mainboard doesn’t run all of the components at their standard settings by default. For our performance benchmarks we manually set the integrated graphics core’s frequency to its standard value to make the comparison with the ASUS P8Z77-M correct.
Gigabyte’s mainboards don’t have automatic overclocking features in their BIOS because the Easy Tune6 utility is supposed to be used for that purpose. However, the utility can't overclock the Gigabyte GA-Z77M-D3H. We don’t even see the Quick Boost tab in the program window. This is due to the fact that this mainboard cannot adjust voltages except for memory voltage. It means our CPU cannot be overclocked to its maximum 4.6 GHz because that requires higher voltage.
It may be possible to overclock the CPU to 4.5 GHz without any voltage tweaking, though. We’ve successfully done that while testing MSI mainboards which cannot adjust voltages by adding or subtracting an offset value to the default level. Instead, you have to fix voltage at a certain level, disabling Intel's power-saving technologies in the process (the voltage doesn’t drop at low loads anymore). This is a typical downside of MSI and EVGA mainboards. Products from other brands are free from that problem.
We found a way to overclock MSI mainboards without disabling Intel's power-saving features. The voltage is just left as it is, but we enable the Load-Line Calibration option that counteracts CPU voltage drop at high loads. By choosing an appropriate value of that option, we can make the CPU stable at 4.5 GHz. Unfortunately, this method doesn’t work with the Gigabyte GA-Z77M-D3H as its BIOS lacks any voltage-tweaking parameters. The 3D Power Control page where you could configure the CPU voltage regulator is missing altogether.
As a result, we had to overclock at the default CPU voltage, so the latter would drop at high loads. We guess we are lucky to have made the CPU stable at a rather high clock rate of 4.4 GHz.
We also increased the memory frequency to 1866 MHz and adjusted its timing. Intel’s power-saving technologies were all up and running.
When you want to make your computer faster, you need to speed up every key component, so CPU and memory overclocking should be complemented with graphics overclocking. The frequency of the Intel HD Graphics 4000 may be theoretically increased from 1150 to about 1300 MHz but we can hardly expect any tangible benefits from that. The integrated graphics core is too weak for resource-consuming games and overclocking can’t change that. As for casual games, the graphics core is quite enough for them even at its default settings. That’s why we didn’t overclock it at all.