One of the most important, if not the most important question we get asked when choosing the best power supply is “how much power do I need in my PC”, overkill can happen, where your PSU (power supply unit) is providing too much power to your components. However, the worst thing is too not power up your components enough or run your power supply so it’s a 100% at capacity.
It’s important not to choose a cheap power supply; sometimes cheap supplies have a higher wattage but will not perform as well as more expensive lower powered power supply.
The first question is, how much power do I really need? There are some great calculators out there to work out the right power supply depending on your CPU and graphics requirements. A great rule to follow is too take about 600W across an average machine and a good 750/800W if you are using 2 graphics card in an SLI/Crossfire setup.
Have a look at these calculators:
Once you have the number from the calculator add about 100watts to it for a single GPU and 200+ for a double GPU, reason being is, you don’t want to max your power supply out as its more likely to fail you also have to take into account surge compensation and electrolytic aging.
Installing a power supply is getting easier because of modern motherboards; they will screw in to most modern cases as all modern PSUs are the same size. The mostly common PSUs from a recent survey conducted on Squidoo show that most people tend to put a 700 – 750W power supply in their system.
Believe it or not, the idea that a 600w power supply will be less efficient than a 450w one is false, your PC will only draw the energy it needs, it’s all about being smart with your power supply, so none of the power is wasted or its running flat out, it is proven that PSUs running at full capacity are more likely to fail.
Corsair, Powercool and XFX are three top brands we would recommend for high quality, long lasting PSUs, choosing an own branded one will be cheaper but nine times out of ten will not be as qualitative as a branded one.
Many suppliers have been involved in the 80 plus certification program. This means that a manufacturer has to validate their power supply units at 80% efficient at 25%, 50%, 75% and 100% of full load meaning you get a better quality power supply. Weight is another great factor, this sounds a bit stupid but it is actually true, usually the heavier a PSU the better quality it is, the cheaper ones will feel flimsy and lighter than your cheap PSU.
Efficiency will save you money on your energy bills, a PSU that is only 50% efficient at 500W could draw double the wattage that is lost to heat alone.
In relation to costs, power supplies are usually very efficient cost wise until you get over 750/800W, if you find an 80 plus certification partner, these prices can dramatically increase, however as said above, you may save yourself a fortune in the long run on your power bills.
The great thing with the 80 plus certification supplies is you are getting what you pay for, and deliver what they are supposed to, some of these systems will go beyond 80% to 85 or even 90!
Chris Turton is a PC tech and gaming blogger, who writes for gaming pc company Palicomp.