PC Perspective posted Intel Core 2 Extreme QX9650 Yorkfield Processor Review

Here's where it gets even better: when running under a full load with 4 threads on CineBench 10 the QX9650 uses 52 fewer watts than the QX6850 based on the 65nm process technology. Only two processors, the dual-core X6800 and E6750 CPUs, run at lower wattages, but they have HALF the processing cores. When we bring in the UT3 testing, the QX9650 is again using 54 fewer watts than the quad-core QX6850 and even less than the dual-core X6800.

Intel Core 2 Extreme QX9650 Yorkfield Processor Review