Gigabyte GA-EX58-UD5 X58 Motherboard Review

Overclocking Results

Core i7 overclocking is quite different then anything else in the past. There are now five clock speeds (CPU/BCLK/MEM/UCLK/QPI) and four multipliers (CPU/MEM/UCLK/QPI) to tweak, as well as eight different voltages. Put simply, there are lot of new variables and potential limitations that an overclocker must now take into consideration. At the moment, no one is an expert when it comes to Core i7 overclocking, and we are all learning new tips, tricks, and tweaks on a nearly daily basis.

Before beginning, you should enter the CPU Configuration menu in the BIOS and disable the CPU TM Function. This will circumvent the "Overspeed Protection" mechanism that limits current draw and CPU power consumption to 100 A and 130 watts, respectively. You are unlikely to ever encounter these limits, but we might as well remove any potential obstacles right off the bat. Secondly, after selecting your BCLK and memory frequency, always set the UCLK and QPI speeds as close to default as possible, in order to prevent them from becoming overclocking bottlenecks. This is particularly important because at the moment it appears that the QPI frequency is the single greatest limitation to Core i7 overclocking (perhaps second only to temperatures), since anything above the 7600-7800MT/s (3800Mhz-3900Mhz) range is nearly impossible to accomplish with any stability. Thankfully, Intel are well aware of this fact, and they are working on providing lower QPI multipliers as we speak.

On similar note, as stated in the BIOS the UCLK must be at least twice the DRAM frequency. Some have argued that the UCLK should be lower than the QPI frequency, but we have had no stability issues when running the UCLK equal to or even above the QPI rate. Some people will argue that HyperThreading should be disabled since it uses more power and causes higher temperatures, but we will leave it enabled in all our tests since we believe it is a central element of the Core i7's appeal.



Living up to its potential, the EX58-UD5 proved to be an excellent overclocker and we were able to increase the base clock (BCLK) from the stock 133Mhz to a heady 209Mhz, which is almost a 57% improvement. This is within 1Mhz of the result we achieved with the hardcore ASUS Rampage II Extreme. Could we expect an even better result from the EX58-EXTREME? We might have to find out...*hint hint*

At the moment, adept Core i7 overclockers can achieve stable 24/7 BCLK results in the 190-210Mhz range, with extreme overclockers having recently reached up to a dizzying 238Mhz, so the fact that we were able to approach the high-end mark reflects very positively on this particular board as well as our prize 965 XE. In order to achieve this result, we had to increase the QPI/VTT voltage from 1.20V up to 1.455V BIOS, which is marginally higher than Intel's recommended 1.35V maximum. Unlike with the RIIE, we did not have to manually tweak IOH and ICH voltages in order to load Windows at these speeds.



As in our proper review, the 6GB G.Skill DDR3-1600 memory kit was able to achieve 1890Mhz 10-10-10-24 at 1.76Vdimm. While this frequency will not impress those used to the blistering DDR3 speeds achieved on the Core 2 platform, the actual bandwidth and latency numbers absolutely decimate all past platforms. In order to achieve this result, we had to increase the QPI/VTT voltage 1.455V, which helped juice the integrated memory controller (IMC) and increase the memory overclocking headroom. Every Core i7 processor has different memory overclocking potential, so it is just as possible that the IMC will bottleneck your memory overclock as the modules themselves. We have no reason to doubt this motherboard's claimed DDR3-2100+ support, but we are not quite ready to subject (& risk) our pricey Core i7 to the 1.55-1.65V QPI/VTT voltage that would likely be required to attain such a high-frequency.

With respect to the much publicized DRAM voltage limit, we can confidently state that all the hype was for nothing. Yes, very early engineering samples were susceptible to damage when high Vdimm was used, but the retail chips are much more robust. What matters the most with respect to this issue is the voltage differential between the QPI/VTT voltage and the DRAM voltage, the general consensus is that it should not be larger than 0.5V.



For our overall stable system overclock, we selected a 4.0Ghz core clock, 200Mhz BCLK, and DDR3-1600 memory speeds.This effectively mimics the clock speeds of a Core i7-920 overclocked to 4.0Ghz, which is what we would run on a 24/7 basis, and it will serve as the overclocked configuration in our subsequent benchmarking section. Before anyone asks, we did not bother overclocking our memory kit because triple-channel DDR3-1600 already provides a huge amount of memory bandwidth and higher memory speeds/lower latencies simply did not result in worthwhile performance improvements, especially when weighed against the increased voltage required to achievement those higher frequencies.