Re: Upgrading to GeForce 6800LE, help required!
I'd go with 6800LE. It's a native AGP card. The only drawback is the power requirement, with only 250W PSU with a P4, 2 HDs and 2 CDs You're on the cutting egge if not beyond the PSU limit.
All 6600GT are Pci-E native with the bridge chip to work on AGP slot, not the best solution and the bridge is famous to be a lemon when overclocked, but the power requirement is a little bit less and you can be more luckly with your PSU.
It's a tough call.