Power Consumption and temperatures
Power Consumption and temperatures
The new Lynnfield based processors have gotten a bit of a redesign and as such they are very energy friendly processors, well -- as long as you do not overclock them.
A processor like the Core i7 870 on average has more performance than a core i7 920 yet consumes only 95 Watt, and that is with all cores stressed. Next to that, clever power management allows the internal voltages and processors multiplier to drop, core independent.
The new Core i7 870 processor has a TDP of 95W, coming from 130 for the Bloomfield Core i7 series that's quite an improvement and it shows this during our measurements:
Power Consumption idle 100% CPU loadMSI Big Bang Fuzion | 870 106 159Intel DP55KG | 870 86 161ECS P55H-A |870 115 170ASUS P7P55D Deluxe | 870 100 171Gigabyte P55 UD5 | 870 92 178ASUS Maximus Gene III | 870 103 179eVGA P55 Classified | 870 111 182As you can see, these are very respectable numbers -- in fact under load the MSI board was the most power efficient. Mind you that this was done with a P55 motherboard, an SSD, optical drive, 8GB memory and Radeon HD 5870 graphics card. For the best power consumption we recommend you to have BIOS features like EIST and C1E enabled and within Windows set your performance mode to balanced (allows the processor to clock down when idling).
Temperatures are very good as well. With an average air cooler you can expect temps like these:
Temperaturesidle
100% CPU load
Core i5 750 (2,66 MHz) 133x20,39
52
Core i7 860 (2,80 MHz) 133x2138
52
Core i7 870 (2,93 MHz) 133x2238
53
This above example was done with a Thermalright MUX 120 air based cooler. Of course results will vary with different motherboards and cooling solutions. But as a baseline the temperatures definitely are promising, especially with overclocking in mind.
100% CPU load is 4 cores 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 split-second.
Overclocking and power consumption
Okay power consumption versus overclocking -- check this out:
Power Consumption idle 100% CPU loadMSI BB Fuzion 100 153MSI BB Fuzion OC Genie (4 GHz) 138 272What a lot of you do not realize is that overclocking a processor can consume heaps of power. We put this to the test by monitoring power consumption with the processor in its default setting and then compared to an overclocked 4 GHz configuration. The results are astonishing, when we stress the 4 (8 threaded) CPU cores 100% at default (Turbo on) we peak at only 153 Watts for the default clocked Core i7 870. But once we overclock to 4 GHz... the power draw all of a sudden is 272 Watts (!) once we stress all CPU cores 100%, so an additional 1200 MHz of power is costing us an additional 119 Watts (!) and we are not even using the GPU for gaming just yet.
Stuff to think about before you start to overclock as the color green turns really red.
