|Intel Core i7-3960X Extreme Edition CPU|
|Reviews - Featured Reviews: Processors|
|Written by David Ramsey|
|Monday, 14 November 2011|
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Core i7-3960X Overclocking
Benchmark Reviews has always been a fan of overclocking, with its historical roots of getting better performance from budget components. It might seem silly (and, frankly, kinda is) to overclock Intel's $990 Core i7-3960X CPU...but more performance is always better, right?
The non-Extreme Sandy Bridge CPUs limit your overclocking in a number of ways: first, since the base clock is used to derive most of the other clocks in the system, to overclock by increasing the base clock frequency is virtually impossible, since increases of more than a few MHz will render the entire computer unstable. This leaves turbo ratio overclocking as the only real mechanism, and while all Sandy Bridge processors can increase their stock turbo multipliers slightly, only the unlocked "K-series" CPUs allow enough headroom for significant performance increases. And you must ensure that the chipset on the motherboard you're running allows this: putting the latest Core i7-2700K in an H67 motherboard will result in a functional computer, but one without any overclocking ability, which is limited to the P67 and Z68 chipsets.
The X79 chipset brings a separate base clock back into the overclocking world, so this time-honored mechanism is again available. The CPU itself adds a new twist: in addition to increasing the voltage to the chip to support higher speeds, you can now increase the sustained maximum and burst maximum current draw as well.
You should consider these overclocking results as preliminary: time pressure and the fact that the only cooler available was Intel's Asetek-sourced liquid cooler (which, while certainly competent, isn't a super-high-end cooler) means that we'll probably see better results in the future. Still, I achieved a solid 4.8GHz clock, sustainable on all cores under load, simply by increasing the turbo multiplier and tweaking ASUS' advanced digital power system on their new TUF Sabertooth X79 motherboard. This motherboard's active VRM cooling helped, too.
The chart below shows how overclocking affected the 3960X's performance on each benchmark, with the stock clocked benchmark score normalized to 1.0 and the overclocked benchmark score represented as how much faster it was than the base clocked benchmark.
The 13% overall performance improvement is less than I'd hoped for, for a 900MHz overclock, but bear in mind that not all benchmarks used all cores, and indeed didn't necessarily load the cores enough to elicit the maximum turbo ratio. In any case, the 3960X is a performance beast even at its stock settings.