I'm running an Athlon XP system with a 400W power supply, 2 CD drives, 2 internal hard drives, and a 15" LCD monitor. Would a 500VA UPS decent enough for about 10 minutes if run time, or should I really get a 650VA version. The difference in size is quite significant, so I'd rather get the 500 if I can help it, but I want something that will do the job.
Go to an auction and get a used one. I got a 900VA for $5, removed the four 6v 10AH batteries and put in two 12v 12AH batteries, it powers my stuff for 45+ minutes and the batteries cost about $20 each with shipping!