Westmere-EX: Intel's Flagship Benchmarkedby Johan De Gelas on May 19, 2011 1:30 PM EST
In the real world you do not run your virtualized servers at their maximum load just to measure the potential performance, but neither do they run idle. The user base will create a certain workload and expect this workload to be performed with the lowest response times. We created a real world “equal load” scenario as we described here.
The numbers above show that there is more to energy consumption than just measuring idle and full load. The quad Xeon needs 67% more energy to run the same workload. Granted, our methodology favors the Opteron a bit: the average CPU load is around 5-30% for the 80 thread Xeon E7, while the Opteron is running at an average of 10-40%. So the load on the Xeon E7 is a bit too low. Still, the real problem is that the Xeon E7 power consumption is high at low loads.