Considering buying an ATI 5750, looks like it's pretty good. Any way I could see if it's compatible
I too, was looking into that card. Go on Newegg and look at its technical details. If yours match to a good extent, it's highly likely that the card is compatible.
Another advantage of the 5750 is its relatively low power consumption. 16W idle, 86W peak.
If you need some insight as to whether you can meet that requirement, Antec has a PS calculator on their website.
EDIT: If your PS supports the extra 20W needed for thde 5770, go for it..,,