Nvidia Geforce 8800GT will come in two flavors, one with 512MB and second with 256MB and both will work at the same clock speed. This time there won't be a GTS and GT or a faster version and the slower one. Nvidia will simply call this card Geforce 8800GT 512MB or 8800GT 256MB.
They will both work on a 600MHz GPU clock and the memory will be clocked at 1800MHz but some overclocking partners will come along with GPU and Shader overclocked versions (SPOC) overclocked cards.
This might be a bit confusing for the end user, but then again whatever makes it run faster is just fine by us.