Our testbed was configured as follows:
- Gigabyte GA-H55N-USB3 rev. 1.0 mainboard (LGA1156, Intel H55 Express, BIOS version F5b);
- Intel Core i3-540 CPU (3.06 GHz, 133 MHz base clock, 4 MB L3 cache, Clarkdale, 1.025 V Vcore);
- 2 x 2048 MB OCZ DDR3 PC3-12800 Blade Series Low Voltage OCZ3B1600LV2GK (1600 MHz, 6-6-6-24 timings, 1.65 V voltage);
- HIS HD 5850, H585F1GDG graphics card (ATI Radeon HD 5850, Cypress, 40 nm, 725/4000 MHz, 256-bit GDDR5 1024 MB);
- Seagate Barracuda XT HDD: ST32000641AS (2 TB, SATA 6 Gbps, 7200 RPM, 64 MB cache);
- DVD±RW Sony NEC Optiarc AD-7173A optical drive;
- Scythe Samurai ZZ (SCSMZ-2000) CPU cooler;
- Zalman CSL 850 thermal interface;
- OCZ GameXStream OCZGXS700 (700 W) PSU with Zalman ZM-F3 fan;
- Open testbed.
We used Microsoft Windows 7 Ultimate 64 bit (Microsoft Windows, Version 6.1, Build 7600), Intel Chipset Software Installation Utility version 126.96.36.1995, and the ATI Catalyst 10.2 graphics card driver.
BIOS Options and CPU Overclocking
As you know from our reviews, same-series mainboards from Gigabyte share the same unified BIOS. The company issues BIOS updates for the entire series of products based on a certain chipset, resulting to both senior and junior models all have basically the same BIOS options. Minor variations are only due to the fact that flagship mainboards are equipped with more onboard controllers. This general rule works for the tiny GA-H55N-USB3, too. You can make sure of that by looking at the following table.
We guess the only thing that needs commenting upon is the semiautomatic switching of hard disk drives into AHCI mode. By default, HDDs work in compatibility mode on most mainboards to avoid any problems. But when you start up this Gigabyte mainboard for the first time, you will be asked whether you want to switch your drives into AHCI mode to make full use of the capabilities of the Serial ATA interface. You can accept or refuse and this message won’t appear again until you clear the CMOS or load the default BIOS settings. That’s very handy.
Like the rest of Gigabyte mainboards, the GA-H55N-USB3 has all the BIOS settings necessary for overclocking and fine-tuning your system. The only thing that is missing is the option of adjusting the system fans rotation speed depending on temperature right in BIOS Setup. Most mainboards from other brands offer this opportunity and we hope that Gigabyte will implement it as well. You have to use OS-based software until then, e.g. Gigabyte’s own EasyTune 6 utility.
Since the GA-H55N-USB3 proved to have the same BIOS options as the rest of Gigabyte mainboards we had tested with our Core i3-540, we selected the already known frequencies and voltages to overclock the processor to 4.5 GHz. The mainboard then started up normally and booted the OS but would hang up as soon as we launched our tests. It would hang up so hard that we could only bring it back to life by disconnecting it from the mains. We suspect that we were limited by the CPU cooler rather than by the mainboard, though. The huge Scythe Mugen 2 that used to help us reach those 4.5 GHz is undoubtedly more effective than the smaller Scythe Samurai ZZ. The CPU was as hot as 88°C under load even when we reduced its frequency and voltage and had been hotter than 90°C, provoking the hang-up, before that. Anyway, when we reduced the clock rate of our CPU by 100 MHz and lowered its voltage, we made the system stable with the CPU overclocked from its default 3.07 to 4.4 GHz.
We want to show you a diagram comparing the results we achieved with each tested mini-ITX mainboard during our Core i3-540 overclocking. The diagram also shows the maximum frequency achievable with our CPU sample: we had reached it with a more advanced cooler which just could not be installed onto small mini-ITX mainboards.
So, the Gigabyte GA-H55N-USB3 is just excellent in terms of CPU overclocking. The difference of 100 MHz from the highest CPU frequency means a 2% difference in performance, which is hardly noticeable without running benchmarks. Well, we’ll talk more about performance in the next section of this review.