What We Recommend
Intel Core i7 920
Thermalright Ultra 120 Extreme
Corsair XMS3 6 GB (3 x 2 GB) DDR3-1600
AMD Radeon HD 4870 X2
Samsung Spinpoint F1 1TB 7,200 RPM
PC Power and Cooling 750 W
Some of the component decisions made in this comparison were influenced by hardware on-hand in the Tom’s Hardware SoCal lab. But we made this project a team effort between Thomas Soderstrom, Don Woligroski, and myself using retail hardware to verify the viability of our overclocks using less expensive components.
As a result, we’re benchmarking with Asus’ Rampage II Extreme and an engineering-sample processor. That particular motherboard isn’t going to be the budget-buyer’s choice, nor is an i7 920 ES going to be representative of retail product. But if you flip over to Don’s $1,250 System Builder Marathon setup, you’ll see he was able to achieve similar overclocking results with the less-expensive Gigabyte X58 motherboard and a boxed i7 920. The real shocker there was that his retail CPU featured memory multipliers that my sample didn’t have—a fact that that Thomas demonstrated in his $2,500 System Builder Marathon story.
As configured, our value-oriented Intel system costs just north of $1,550 at the time of writing. Bear in mind that only four components differ between the AMD and Intel builds: motherboard, processor, heatsink, and memory. We’ve kept everything else the same in the interest of comparing performance in an overclocked environment.
There is no longer much mystique behind Core i7 overclocking. The non-Extreme models have locked multipliers, so extra performance comes from Bclk adjustments. Tweak your Bclk, your processor voltage, memory multiplier (the retail boxed product gives you a lot more flexibility than a tray or engineering sample chip does), and QPI voltage.
We were able to boot at 4 GHz and run fairly stable at 3.9 GHz. However, even at the 3.8 GHz setting on which we eventually settled, we saw load temperatures peaking at 85 degrees Celsius. For day-to-day usage, that’s plenty aggressive, thank you very much. Our final settings were a 20x CPU multiplier, 190 MHz Bclk, and stock voltages all of the way around.
Hopefully, these settings take into account the variance you'll see from one CPU to another, since we wouldn't expect every 920 to hit 4 GHz.