20 pin ATX connector vs. 24 pin

[pulsedrive]

I know that the newer 24 pin connectors are meant to help supply power to the PCI E slots for higher end video cards, but I wanted to know will it make a difference with an x7000 pro. Because it looks like the PSU in the original case I got has gone bad, I have a new one in it right now, but I am probably going to return the old one and then new one and get a completely different case + PSU. The replacement PSU I got has the newer 24 pin, and seems to work fine, but then again so did the other one till it blew out. Any help is appreciated.