Windows 7: GTX 480/ Radeon HD 5870 and my PSU

So I was looking towards getting the GTX 480 or 5870, but was unsure if my PSU was compatible with either or whether I'd have to buy a new one. I'm pretty sure the 5870 will work, but I'm not sure about the GTX 480, so some help would be awesome!

This is what I have, it's a XION 630 Watt ATX 12V Power Supply

Thanks in advance!

I'm not expert in psu but I think it could handle it.

That psu gas a 6 pin and a 8 pin right? Because thats the requirement mentioned on nvidia website.

You have 2 +12v rails 1. at 21Amps and th other rated at 22Amps. So those are the numbers you need to know in order to check the +12 Amp ratings of the 2 cards you have in mind.

Remember it's not so much the wattage as it is the Amps delivered on the +12v rail(s) that will determine if your power supply can run a specific piece of hardware. Also the effiency rating comes into paly, you want to have a power supply with a miminum of 80% effientcy rating. Fabe
Also it only has 2 6pin PCI-e connetors so it you need a 6 pin and a 8 pin You will need soem kind of an adpater.
I'm also a firm believer in not skimping on your power supply. It is a very important core component to your system and should buy a qality branded Power supply. Such as a Corsair. OCZ. Thermaltake, Vantec, Sea Sonic Not neseccarily in that order.