One of the most common questions of PC building is, "How much power do I need?" And while I realize that most Maximum PC enthusiasts might very well just answer the question thusly--"As much as I can buy"--that's not always the best recommendation for two key reasons: You don't need a kilowatt power supply if you're rocking a newb rig, and you might not have the budget to afford more juice than what your computer ultimately requires.
But how, then, do you figure out the exact size of power supply your system requires for perfect performance? It's no easy task. I highly doubt you want to arm yourself with a clipboard and surf over to the manufacturers' Web sites to figure out the power draw for all the components in your rig. And even then, you're not going to have an easy time doing so. You'll probably just go off the recommendation of someone from an online message board--"oh, so and so rig usually needs... 700 watts at least. You'll be fine then. Word."
That, or you could hit up this week's Web App pick: the eXtreme Power Supply Calculator. This super-helpful online tool gives you a comprehensive list of components to pick from. Select what's in your PC and you'll get an read-out of how much power your system will likely draw in the form of a recommendation for the specific-sized power supply you should pick up. It's as easy as that.
But just how comprehensive is this tool? You can pick:
CPU type (by actual product)
Video card (by actual product)
Hard drive (by RPM)
Optical drive(s) (by type)
PCI cards (by type)
Miscellaneous PCI Express cards
External USB or FireWire devices
Cold Cathode lighting
Fans (by size and type)
Coolers (by type, with extra information for water coolers)
In short, if you aren't using the eXtreme Power Supply Calculator, there's a good chance you could be running a power supply that's too big or too small for your system's needs.
Every Thursday, Maximum PC picks a new Web App as its favorite of the week. Have a Web App that you can't live without? Twitter David Murphy @acererak with your latest suggestions.