The Sandy Bridge-E processor's idle power consumption is in-line with the existing Sandy Bridge processors, sipping along at about 100W. What's surprising is how efficiently the workstation processor shuts off unnecessary portions of the CPU to achieve an idle power draw equivalent to a mainstream processing platform. Power savings compared to the old hex-core Core i7-980X is about 40%!
With heavier workloads such as the 3DMark Vantage CPU test, we see the effects of a 130W TDP based processor as compared to the 95W TDP rating of the Sandy Bridge CPUs. Naturally the Sandy Bridge-E processor consumes more power but it was still better than its predecessor and the AMD counterparts. but the 4-thread rendering test of 3dsmax04 seems to show an exception in this situation.
Interestingly on SPECviewperf 10 when setting the workload for four threads, the six-core processors consumed less power than their quad-core based mainstream Sandy Bridge counterparts. Either the scheduling isn't very efficient and the presence of CPUs with more cores enabled them to complete the workload sooner, or SPECviewperf 10 and the OS are actually taking advantage of the multi-core processors to schedule workloads as sooner than expected. Either way, the result is clear that heavily threaded workloads get to complete faster on the six-core processors, thus consume less overall power.