Thermaltake Power Supply Calculator

Some of the hardware developers have created webpages over the past few years to try and help you work out the rough size of PSU your system needs. This includes some of the memory makes, the CPU makers and the PSU makers themselves.

But for me the best one is the Thermaltake Power Supply Calculator.

http://www.thermaltake.outervision.com/index.jsp

This is a very comprehensive calculator, giving you the ability to select all of the components you have in your PC, right down to selecting exactly what the graphics card is, how many IDE or SATA drives you have, and even the number of devices connected by USB.

This is quite an accurate tool. I worked my main systems power needs out just now and I was happy to find that my 600W PSU is easily big enough for the moment, with my current setup needing just 340W. And it will cope with the extra couple of SATA HDs and newer graphics card I currently have planned. All totally 430W at maximum load to all components at once (which rarely happens).

Mine needs 288W according to the test, I tried to be as accurate as possible, but I could have missed something. And my PSU is a 500W (I think), it's an Enermax.

More than enough overhead for your current PSU then. Remember that this gives you the maximum power consumption for all components running at full power, which isn't normal.

Did you also add the 20% at the bottom right of the page for a PSU being used for over 1 year? That added a bit to my Wattage result but was still well within requirements for my current setup.

I was surprised a bit, because other guides have always recommended bigger and bigger PSUs, whereas in reality from this test it shows they are not needed unless you are going to be running two graphics cards in SLI mode.

I did do some testing and adding two more sticks of ram to a system does increase the total quite a bit, as does added newer graphics cards. Other things like HDDs don't use much at all though.

I'd hate to think how much of my 450w PSU is being wasted on my Miggy (when everything is working of course).

I didn't add the 20%, but I guess 288 is still far away from 500, so I might be on the secure side.

Hmm my current setup needs 311w add 20% 373w and I have a 400w supply so I am on the verge there, I did put in a couple of extra usb devices though just because I do occasionally stick a couple of things in there. Will be useful when I finally get round to building my new pc, whenever that may be.