Between those two I'm not sure which is "better". The Xigmatek has more usable power. 34A vs 28. But at least I know who made the Corsair. Either of those will power your 9800GT. A typical system with the 9800GT needs 22A.
just as a question are you going to buy this graphics card (wouldn't reccommend it) or do you already have it?
I was going to get it, Is there a better one available? Because I need a graphics card that:
Is Nvida (My Chip Set Is Nvida)
Can be used with a power supply that cost about 30-50$
Is compatable with pci express x16 1.0