Intel's Sandy Bridge-E To Ship Without Stock Cooler, Thermal Conclusions Questionable

Sandy Bridge processors have been available for eight months, but Intel's highest-end CPU remains based on the older 32nm Westmere architecture, rather than on SB silicon. A report from VR-Zone suggests Intel's Sandy Bridge-E CPUs may have been delayed for thermal reasons. According to the site, Sandy Bridge-E chips will ship without an Intel standard cooler and may dissipate as much as 180W. To date, Intel has said only that the upcoming processors will have a TDP in line with its previous high-end desktop chips.

The upcoming socket will span enthusiast and server systems.

Despite appearances, the two statements aren't necessarily linked and should be evaluated separately. Any decision Intel makes not to ship a stock cooler is going to be based on how often said coolers are actually used. The vast majority of boutique OEMs emphasize upselling customers on both CPU overclocks and CPU cooling, even in cases where the CPU is cooled more than adequately by the default Intel solution.

Intel's X79 chipset will use the company's all-new, high-end LGA2011 socket--a socket they'll share with upcoming Xeon processors that aren't expected to launch until early 2012. There's no indication that Intel won't have a stock heatsink+fan design ready for the Xeon products; the company's decision (if true) not to launch an enthusiast stock cooler in the face of widespread third-party support is almost certainly a business decision as opposed to a thermal one.

With that said, the question of CPU TDP deserves a bit of attention. When we reviewed MainGear's Shift last year, we measured the system's total power consumption running Prime95 at 4.2GHz (the speed of the system as shipped) and at 3.33GHz (the stock speed of the Westmere-based i7-980X.) In the Shift's case, raising the CPU clock by 26 percent increased total system power consumption by a whopping 37 percent. Much of that jump--about 60 percent of it--was driven by increased voltages. Given the rate at which power consumption can climb when voltages and frequency are both adjusted upwards, it's not unreasonable to think that top-end LGA2011 chips could draw comparably large amounts of power when overclocked. In its base configuration, the i7-980X is rated as a 130W TDP processor--a figure that seems reasonable, based on what we see above.

VR-Zone, however, states "these beasts are consuming closer to 180W and that's without even overclocking them. In fact, according to PSU design guidance we've seen, Intel is telling power supply makers to make sure their Sandy Bridge-E PSUs can cope with a peak current of 23A on the 12V2 rail..."

Being able to provide 23A of peak current across the 12V rail has precious little to do with a sustained 180W TDP. VR-Zone's figures, if accurate, imply that Intel's Sandy Bridge-E CPU's draw far more power than one would expect based on the performance of both Westmere and quad-core Sandy Bridge. It's certainly possible that the first generation of hexa-core Sandy Bridge chips missed Intel's thermal guidelines, but we're not willing to conclude that's the situation as of this writing.