In the reviews, one person tried it with a 160W PSU and it didn't work and I would ignore the one who claims that a 550W PSU is required. Since that video card draws little current, I'd give it a try. It's impossible to confirm that it will definitely work since we don't know if your PSU is a quality or a cheap unit.
Well, the card is $59.99 at newegg, which I have...the $300-$400 to upgrade the whole system I do not have. Maybe I should rethink the whole thing. Wouldn't I see a performance increase from the Radeon 8500 64meg card that I currently have?
That card isn't very fast, but it's much faster than the 8500 (which is rather old by current standards). Upgrading from an 8500 to a 9800 Pro was a significant improvement and the X1650 Pro is much faster than the 9800 Pro.
it should work... of course if the psu has really weak 12V line it might not. care to take a look at the sticker on the side of the psu? It should say how much amperage/watts it can supply at different voltages.