The results of performance tests for Core 2 Extreme QX6850 and other processors with 1333MHz bus were quite predictable, however we can’t say the same thing about the power consumption measurements. On the one hand, the newcomer works at higher clock speed that linearly affects the power consumption, but on the other hand, it is based on the new processor stepping that Intel claims to be more power efficient. Therefore, to find out the real state of things, we decided to measure the power consumption of test systems featuring different processors.
The first measurement was made in idle mode. Enhanced Intel SpeedStep and AMD Cool’n’Quiet technologies were activated.
In idle mode Core 2 Extreme QX6850 is not really economical compared with the other solutions on Core micro-architecture. The thing is that since this CPU supports 1333MHz bus, it can only lower its frequency to 2.0GHz in case of low workload, while processors with 1066MHz bus can drop their frequency down to 1.6GHz. Although the power consumption of Core 2 Extreme QX6850 processor look still very appealing against the background of AMD processors: it turns out even more economical than AMD Athlon 64 X2 6000+.
The second session was performed with 100% CPU utilization. We used Prime95 utility for this matter.
The situation is very similar: Core 2 Extreme QX6850 is again the leader among CPU with Core micro-architecture. However, here we can also see the real advantage from the new optimized G0 processor stepping. The power consumption of the 3GHz Core 2 Extreme QX6850 processor gets really close to the results of a quad-core CPU with 2.66GHz speed based on the older processor stepping. And if we compare the power consumption of quad-core processors based on different steppings but working at the same 2.66GHz frequency, we will see that the new G0 revision allows saving about 20W in burn mode and about 5W in idle mode.