there isnt any specificatin difference of th actual hardware, just that retail comes in box and other opened with the drivers only.
get OEM, as i'm as well using just the card and drivers, though i have retail ZS
Intel Core2Quad 2.66Ghz 12MB L2-Cache
4096MB DDR Kingston Hyper-X
XFX 9600GT AlphaDog
Seagate 2 X 320GB SATA2
LG L246WH Flatron 24"