Power consumption

With its smaller size and lower transistor account, you'd naturally expect the Coe i5 750 to consume less power than its bigger brothers, but is that actually the case?  Let's check it out by measuring the power of our test system as a whole, first when idling at a Windows 7 desktop, and then again under load by using Prime 95's power-hungry "in-place FFTs" test across all of the CPU's cores to measure power usage under heavy load.

At idle, our Core i5 750 consumes over 40 Watts less than the Core i7 920 - A number which edges closer to 50 Watts once we put our system under a CPU-intensive load.

CPU temperature

So, the Core i5 750 is less power-hungry than its older siblings, but what of CPU temperatures?  Let's take a look at how it compares to a Core i7 920 while making use of that aforementioned Noctua NH-U12P cooling solution.  Again, we'll be examining temperatures both when the system is idling at a Windows 7 desktop, and then again after a thirty minute period of running Prime 95's "in-place FFTs" stress test.

Neither CPU gets particularly hot at idle (and they both sensibly reduce clock speeds quite aggressively when idling provided SpeedStep is enabled in the BIOS, as it is here), but the Core i5 is slightly cooler overall.  Interestingly, temperatures seems to vary more between CPU cores on the Core i5 750, although without further testing it's difficult to say if that's down to the architecture of this new CPU or just an anomaly due to the application of thermal paste or the like.

After a protracted period under full load, there's no doubting which CPU is cooler any more, with the Core i5 750 displaying tempatures up to twenty degrees cooler than the larger Core i7 920.  If you're worried about heat in your new system, then the Core i5 is an undoubtedly cooler computing experience in that discipline, which in turn leaves more room to find a quieter, less imposing cooling solution to affix to it if you're not too worried about overclocking.