I am really confused about Battery Back-UPS's. I have a APC Back-UPS ES 550 it says it can do 330 watts/ 550VA, but the thing that confuses me is that my computer has a 470 Watt Power Supply, plus a 22 inch flat screen monitor, so theoretically it should over load, but it does not, when the power goes out it stays on. I was going to get a second one for my Playstation 3, it was a 350VA/ 200 Watts, but I notice it says in the book that the Playstation 3 uses 380 Watts. My question is so how do I figure this out, which is the right one to buy? Thank You, Jesse My Maxed Out Pentium 4! Dell Dimension 4600 Pentium 4 HT @ 3.4GHz 4GB DDR Ram (2x500GB) SATA II Drive Windows Vista Ultimate NVIDIA 7600 GT Computing.net Member since 2003!

Power supply ratings aren't meant to imply that they are drawing a certain wattage (volts*amperes) from a source, just that the "peak" that they supply (usually during powering up---and most figures are overblown because most users seldom need that much) is a given amount. Your 470 watt supply means that it can supply 470 watts to the machine (not draw from the UPS) at a given peak moment. If your machine needed 470 watts continuous, then you'd be looking for a room air-conditioner before long, and your UPS would keep up for about a millisecond if it were drawing that much. Maybe the PSU calculator can explain further: http://www.extreme.outervision.com/...

My question would be, do you really need it. I doubt it would be the answer. Just a waste of electricity. You'd need an amp meter to show what you use. "Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10