According to what we are hearing now, Nvidia's reference GTX 460 card is the one with a 192-bit memory interface and 768MB of memory, while the 1GB version with a 256-bit memory interface will be done by partners. This also means that the 1GB version could end up with better non-reference cooling.
A lot of partners are concerned regarding the current situation as the GTX 460 1GB might end up faster than the GTX 465, at least in certain scenarios. The concern is legit and if the performance of the GTX 460 1GB comes close to the GTX 465 these cards will sell a lot better than the GTX 460, and as you would have guessed, it means that partners will get stuck with a large stock of GTX 465 cards.
We all saw the picture of the reference GTX 460, and according to our sources, that is the one with 768MB of memory. We might even see a situation where some partners will not even go for the 1GB version, at least not until they clear their GTX 465 inventory. In this case, the fully enabled GF104 might take a while before coming to the market.