So I've got a Celeron 400mhz bookPC (Dell) system w/ 20gb hdd and a SB16 soundcard in my car, that works very nicely on a 300w inverter (thanks again for the tips on making THAT thing work nicely guys!).

I'm currently considering raping another home machine I have to build that carPC up to a 1700mhz Athlon w/ 256mb DDR2100, and adding an AM/FM tuner card on a 250w power supply. Now I know that I will probably not NEED a full 250w supply to drive it, but I'd like to know how much a rig like that will draw under it's worst load. I don't want to pop for the case and everything if it won't work with what I have, but I keep reading posts here from people running 2ghz+ rigs on inverters and such.

What do y'all think? Will it work with what I have?