High CPU and GPU Utilization
The results of LinX are indeed very high, but they aren’t yet the maximum, because this utility only loads the CPU. in order to also load the GPU we launched another graphics test, Furmark, simultaneously with LinX. This test initiates maximum graphics card power consumption. This is what the average power consumption readings taken off this artificially created environment look like:
Well, there is nothing to comment on here. Overall, we see exactly the same thing as in the previous graph. Only the absolute numbers have become higher, which is in fact quite logical, since the graphics card did contribute its fair share this time. However, even though we managed to significantly increase the power consumption of our test platforms in this somewhat artificial test compared with the results we have just seen under more realistic operational loads, the power supply makers will obviously be disappointed. Even the most power-hungry LGA1366 system consumes no more than 500 W of power. As for the power consumption of all other tested platforms, it never exceeded 350-400 W.
Absolute Maximum Power Consumption
Although we tried to recreate maximum possible load in our previous tests, we still can’t use these results to determine the required power supply capacity. The thing is that we have dealt with average results, which do not coincide with the peak ones even when we used special utilities loading the CPU and GPU to absolute maximum. It mainly occurs because the power consumption of the graphics sub-system is extremely uneven: it needs dramatically different amount of power for rendering a frame and then displaying it on the screen. That is why we decided to add one more diagram to what we already had: it shows absolute maximum power consumption of the platform in question registered over the entire test period. These numbers will allow us to conclude what PSU capacity we will need for our overclocked system in every given case.
Contemporary systems based on non-overclocked processors and equipped with a single-GPU graphics card, can in most cases be just fine with a quality 300-400 W power supply unit. Moreover, 400 W capacity will only be needed for the most resource-hungry quad-core processors like Core i7 or Phenom II X4. 400 W PSUs may also be quite enough even for overclocked processors, when its core voltage is not increased. However, if you intend to boost your system performance more substantially by overclocking it, then you absolutely need a serious power supply system. And as you can see from the obtained results even a 500 W power supply may turn out not good enough in this case. For example, when we overclocked our Core i7-950 processor to 4.2 GHz, the maximum power consumption hit 530 W. and that is also not the highest possible number, I should say, because this time we didn’t overclock our graphics card, which may make a significant contribution to the total system power consumption as well.