When you're trying to figure out how much juice your next PC will need, you usually end up with a capacity of between 500 and 700 watts. Since power supplies range in price from £50 to £125 and upwards, how much do you really need to spend on a reliable and quiet PSU? Hardware.Info tested 43 power supplies to answer that question for you.
The trend has been heading in the right direction for a while now. For years new PCs kept becoming more and more power hungry, but these days the average PC is actually getting increasingly energy-efficient. Of course the high-end segment is still the exception to the rule, but a powerful PC will no longer make you the favourite customer of your electricity company.
The TDP (Thermal Design Point, or the maximum energy consumption) of most current processors is around 65 or 95 watts. Only Intel's high-end Socket 2011 and certain AMD models require a maximum of 130 watts. Most high-end graphics cards like the AMD Radeon HD 7970 use 250 watts at most, but usually much less. The motherboard and the memory modules use another few dozen watts, the hard drive around five watts and then a couple of watts for the case fans. All together a modern PC with, for example an Intel Core i7 3770K processor and AMD Radeon HD 7950 video card, should never exceed more than 350 watts. With a Core i7 3960X and AMD Radeon HD7970 another 100 watts is added.
This means that for an up-to-date and capable PC with one graphics card, a PSU of 500 to 600 watts is more than enough. If you plan on doing a lot of overclocking or want to add another video card, then you're looking at 650 to 700 watts.
Power supplies with a capacity between 500 and 700 watts are therefore popular among PC enthusiasts that enjoy building their own systems. You can read the rest of Megatest: 43 PSUs from 500 to 700 watt on Hardware.info.