If the PSU does not have any labels, like what Amp on the +12V rail, and I guess it can't power up either gts 250, HD 5770 and 8800gts. Because like the gts 250, which requires lowest Amp and wattage, it will need a 450 W PSU with 24A on the +12V rail, so buy this one if you want. If the power does not handle the GPU, you need to buy a good PSU.