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 for example has roughly sometimes even 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.
All three processors launched today have 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 load |
| Core i5 750 (2,66 MHz) 133x20, |
124 |
154 |
| Core i7 860 (2,80 MHz) 133x21 |
124 |
161 |
| Core i7 870 (2,93 MHz) 133x22 |
124 |
163 |
As you can see, these are very respectable numbers. Mind you that this was done with a P55 motherboard, an SSD, optical drive, 8GB memory and GeForce GXT 280 graphics card.
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).
Temperatures are very good as well. With an 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 was done with a Thermalright MUX 120 air based cooler. Of course results will vary with different mother boards and cooling solutions. But as 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 check this out:
Power Consumptionidle
100% CPU load
Core i7 870 (2930 MHz) 133x22124
162
Core i7 870 (4130 MHz 188x22) 1.425v137
285
What a lot of you do not realize that overclocking a processor can consume heaps of wattage. We put this to the test by monitoring power consumption with the processor in its default setting and then compare to an overclocked 4,1 GHz configuration.
The results are flabbergasting, when we stress the 4 (8 threaded) CPU cores 100% at default (Turbo on) we peak to only 162 Watt for the default clocked Core i7 870.
Once we overclock towards 4.1 GHz ... the power draw all of the sudden is 285 Watt (!) once we stress all CPU cores 100%, so an additional 1200 MHz of power is costing us an additional 123 Watt (!).
Stuff to think about before you start to overclock as the color green turns really red.
