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Intel Core i7-3960X Review: Sandy Bridge-E And X79 Express

Cooling And Overclocking Core i7-3960X

Intel isn’t bundling its Sandy Bridge-E-based Core i7s with a cooling solution of any sort. Perhaps the company surmised that few power users willing to drop 10 bills on a flagship processor stick with boxed heat sinks. Instead, it’s selling a closed-loop water cooler and cost-optimized heat sink/fan combination separately, allowing enthusiasts to pick between two options from Intel or a host of other third-party products. 

Intel expects the liquid propylene glycol-based cooler, sourced from Asetek, to sell for somewhere between $85 and $100. That part is compatible with Sandy Bridge-, Ivy Bridge-, Sandy Bridge-E-, and future Ivy Bridge-E-based processors. Several other third-party liquid coolers are expected to accommodate motherboards with the LGA 2011 interface, too.

Intel’s heat sink and fan combo should go for less than $20, though that part is aimed at government and business customers who might look to Sandy Bridge-E for an entry-level workstation. That’s not to say there won’t be plenty of high-end air coolers for LGA 2011, though. Noctua sent us its NH-D14 SE2011 for our upcoming holiday gift guide, and we were able to get all six cores stable at 4.6 GHz running Prime95 for an hour  with it on the Intel DX79SI board.

Now, I don’t put much stock in overclocking results from processors sent out to reviewers. But I spent some time polling system builders who were preparing to sell overclocked Sandy Bridge-E machines at launch, and it seems like 4.5 or 4.6 GHz is a realistic target for enthusiast-oriented PCs that (hopefully) won’t fizzle out and die within a month.

Overclocking Sandy Bridge-E

There are only three Sandy Bridge-E-based processors at launch, and only two of them are expected to be available. That pair of chips is multiplier-unlocked, making overclocking a fairly simple matter of setting a ratio and fine-tuning with BCLK settings.

The third model, Core i7-3820, isn’t unlocked, though. Instead, it’s “partially unlocked.” Intel lets you set a multiplier six bins higher than the highest Turbo Boost clock rate: 3.9 GHz. The result is a maximum of 4.5 GHz using ratios exclusively.

Unlike the Sandy Bridge/Cougar Point combination, however, the clock generator for this platform is external, which makes it easier for you to make BCLK modifications without running afoul of buses more sensitive to deviation. In order to facilitate this, you get a handful of strap ratios that increase the BCLK without pushing subsystems like PCI Express out of spec. In short, though Core i7-3820 overclocking is technically not unlocked, a combination of extra multiplier settings and PCIe/DMI ratios should make it possible to find the quad-core chip’s limit fairly freely, too.

Asus' 100, 125, 166, and 250 MHz strap settings