8800GT OC vs 8800GTS

Ok, according to the graphics info on Tom's Hardware (the FPS charts), the GT OC is going to be faster; much faster. But I'm just wanting to make sure I'm making the right choice as sometimes higher numbers don't mean better performing chipsets...

Here's my choices:

Leadtek WinFast PX8800 GTS TDH GeForce 8800GTS 640MB 320-bit GDDR3 PCI Express x16 HDCP Ready SLI Supported Video Card (http://www.newegg.com/Product/Product.aspx?Item=N82E16814122018R)

vs.

GIGABYTE GV-NX88T512HP8 GeForce 8800GT 512MB 256-bit GDDR3 PCI Express 2.0 HDCP Ready SLI Supported Video Card - Retail
Equipped with Ultra Durable 2 technology and Zalman fan (http://www.newegg.com/Product/Product.aspx?Item=N82E16814125087)

I'm really thinking that GIGABYTE is going to be the better choice, however, my mobo isn't a 2.0 slot. From my understanding, 2.0 cards are compatiable with 1.0 (or 16x) mobos. Is this true? and is this GIGABYTE a heck of a deal?

Thanks a ton man. I was hoping my tech skill in reading this stuff wasn't obsolete. That's what happens when you start working in retail