We tested Gigabyte GA-EP45T-Extreme mainboard in an open testbed with the following hardware and software components:
- Mainboard: Gigabyte GA-EP45T-Extreme, rev. 1.0, BIOS F4;
- Intel Core 2 Duo E8400 (3.0GHz, 333MHz FSB, 6MB L2 cache, Wolfdale, rev. E0, 1.25V Vcore);
- Intel Core 2 Quad Q9300 (2.5GHz, 333MHz FSB, 6MB L2 cache, Yorkfield, rev. M1, 1.175V Vcore);
- Memory: 2 x 1024MB DDR3 OCZ PC3-14400 Platinum Series OCZ3P18002GK (1800MHz, 8-8-8-24, 1.95V voltage);
- Graphics card: ATI Radeon HD 4870 512MB;
- HDD: Samsung SP2504C (250GB, SATA II, 7200 RPM, 8MB cache);
- CPU cooler: Zalman CNPS9700 LED;
- Thermal compound: Noctua;
- PSU: Antec NeoPower HE 550 (550W);
- OS: Microsoft Windows Vista Ultimate SP1 (32-bit).
The initial test with Intel Core 2 Duo E8400 processor with the clock frequency multiplier lowered to the minimal x6 showed that that the board can boot the OS at up to 590MHz FSB frequency. This is very good result. Our CPU sample can overclock up to 4320MHz (480 x 9). Simple calculation revealed that you can obtain this frequency at 576MHz FSB and x7.5 multiplier (576 x 7.5 = 4320). Our test applications confirmed that the system was operational in these conditions*:
* - the utility “doesn’t see” that the processor clock frequency multiplier was lowered; it believes that the multiplier is still at its nominal value that is why it reports higher CPU frequency.
In was a little upset with the fact that x3.2 memory multiplier didn’t work during overclocking. In this case we could get our memory to work at 1843MHz. This multiplier does work in nominal mode. Moreover, it is a default multiplier setting the memory frequency at 1067MHz for CPUs with 333MHz bus. However, we could use x2.66 multiplier and in this case the memory worked at 1536MHz. In the end, it was totally pleasing that even with the minimal memory multiplier of x2 when it worked “only” at 1382MHz, the timings could be lowered to 6-6-6-18 and Performance level set at 9. The system remained stable and Prime95 needed only 2 minutes 14 seconds to calculate 8 million digits – our little lab record. This is the first time we see numbers like that. When we overclocked the same processor to the same 4.32GHz frequency in a system with DDR2 SDRAM, the result was much lower.
Far not every mainboard can work with CPUs overclocked to their maximum at 576MHz bus frequency. However it is not very hard to find a good board that can overclock a dual-core CPU to its maximum speed, even if it has to work with lower FSB frequency. When it comes to quad-core processors, things are not as rosy any more. Most mainboards that cope quite well with dual-core processors overclocking usually stall at around 450MHz FSB with quad-core ones. Rarely a board can work with a quad-core CPU at 470MHz FSB; and only two solutions could hit the maximum – 490MHz FSB – with our Intel Core 2 Quad Q9300 processor. Gigabyte GA-EP45T-Extreme mainboard has become the third one to succeed: it conquered 490MHz FSB speed with a quad-core CPU!