I wouldn't use it but it should work in theory (I don't trust the brand at all though). I would just buy a good 500w one from one of these brands (in no specific order) OCZ, Antec, SeaSonic, XFX, PC Power & Cooling and Corsair. The 6870 uses two PCI-E connectors and your current PSU only has one, you could connect it using adapters (if they come with the card you pick) but I don't trust adapters. So the short answer is yes(should) but NO(just don't). Don't use that PSU.