Power Consumption
Along with performance and overclocking comes the all important issue of power consumption.  Intel promised a lot of improvement with idle power consumption and active power consumption by being able to enable cores individually as opposed to the all or nothing way the Core 2 design functions. 

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** Note: the Core 2 Q9650 power consumption results are not included here because the processor was “simulated” with the QX9770 that prevented real-world Q9650 power consumption from being measured.  Performance, however, was identical.

Idle power consumption shows a couple of interesting points: namely that the Core 2 processors at idle are just flat out using less power than the Core i7.  With all of the work that Intel put into power consumption optimization, how is that possible?  Quite frankly, we have a lot of new technology at work here including a new three channel memory controller and a new QPI interface to power and that higher performance requires a bit more power.  We are talking about 14 watts between the QX9770 and the Core i70965 EE CPU – not a small amount exactly but it is still less than our AMD Phenom X4 test bed.

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Under a full load of CineBench 10 the story on Core i7 doesn’t really look any better – the i7-965 EE uses about 64 watts additional power than the QX9770 and even the Core i7-920 uses more power as well. 

What is more interesting to look at is how single threaded power consumption compares across both platforms. 

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What we have here is a comparison of the Core 2 QX9770 and the Core i7-96 EE CPUs running at full multi-threaded capability and then also with just a single thread running under CineBench 10.  You can see that the Core i7-965 uses 83 watts less power when only running a single of the four cores under load – that is a 41% drop in total system power!  In comparison, the QX9770 platform only drop power consumption by 17% when loading a single core indicating that Nehalem has much improved efficiency even if it still uses more power than the Core 2 design.

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