I've already paid for the 8500 unfortunately.

It is a Sparkle 8500GT 256MB DDR2 HDTV DVI VGA DX10 PCI-E.

Does the manufacturer make any difference?

Oh well, I guess I can try it out and if it doesn't fulfill my expectations I can always send it back or put it on eBay.

I am planning to use Normal Mapping a lot as well as other shaders.
Is it up to the challenge? For example, Could it run something like The Elder Scrolls, Oblivion at a decent frame rate?

Thank you.