Nvidia went a little different on these GPU's and both models have 336 Shaders but they have subtle differences in design. The 1GB model has a wider memory bus at 256 bit and the 768MB card has 192 bit memory bus. Having two GTX-460's is a little confusing so we will be referring to them as the GTX-460 768 and GTX-460 1GB. The GTX-460 1GB has 32 ROPs and the 768MB model has 24 ROP's. SO our major differences on the two card are the 1GB card has 256MB more memory, 8 more ROP's and 64bit more memory bus. The projected prices on the cards are $199 for the 768MB model and $229 for the 1GB model.If you are stuck on a monitor with 1680x1050 resolution then the 768MB model will probably be great, if you plan on going to 1920x1200 or have a 1920x1200 monitor then it's likely you'll want the 1GB model. For the extra $30 bucks we'd say hold out and get the 1GB model, thirty bucks for a small measure of future proofing is a small price to pay.