Power Consumption and temperatures
Power Consumption and temperatures
The new Core i7 processors have gotten a bit of a redesign and are relatively (in the widest sense of the word) energy friendly processors, well... as long as you do not overclock them that is. Next to that, clever power management allows the internal voltages and processors multiplier to drop, core independent.
Our processor has a TDP of 130W, which is similar to the initial Bloomfield Core i7 quad-core series. This processor being a quad-core, that's quite an improvement and it shows this during our measurements:
CPU | IDLE (Balanced) | Idle (High perf) | 100% CPU |
Core i7 965 + 5870 | 142 | 152 | 224 |
Core i7 965 @ 3.9 GHz + 5870 | 172 | 173 | 292 |
IDLE Balanced is the OS configured in BALANCED energy mode, with speedstep throttling down the processor. In IDLE we draw roughly 140W, that's with one ATI Radeon HD 5870 graphics card installed, yet the GPU in IDLE.
If we move the Windows 7 or Vista energy mode up to performance we see the wattage rise to 150W still in IDLE. Now once we STRESS the multiple cores we see a power draw of 224W (for the total PC, measured at wall socket).
Once we overclock to 3.9 GHz on all four cores (we'll show you that in the next chapter) things get out of hand much quicker, we now measure a peak of 292W.
For the best power consumption make sure you have BIOS features like EIST and CE1 enabled and within Windows set your performance mode to balanced (allows the processor to clock down).
Let's have a look at processor temperatures, based on quality heatpipe cooling. Temperatures are very good under control. With an air cooler you can expect temps like these:
Temperatures Degrees Cidle
100% CPUTIN
100%CPU Core
Processor
36
50
56This test was conducted with a Noctua NH-D14 air based cooler. Of course results will vary with different motherboards and cooling solutions. But as baseline the temperatures definitely are promising, especially with overclocking in mind we have plenty of headroom left.
100% CPU load boils down to 4 cores / 8 threads 100% stressed with Prime 95, voltages are left at default, processor Turbo mode is enabled. Overclocked temps of course will differ, but we'll show you that in a second.