According to the source, Asus will initially be offering two versions of the 8800, the EN8800GTX and the EN8800GTS. The EN8800GTX/HTDP/768M as it is called will come with an absolutely massive 768MB of GDDR3, relying on a 384-bit wide interface. The “lower” model, the EN8800GTS/HTDP/640M, will have 640MB and a 320-bit interface, which seems like an odd configuration. The GPU of the GTX will operate at 575MHz and the memory will operate at 1.8GHz.
As the article mentions, much information about the G80 is still unknown and could change. With no official comment coming from nVidia or their vendors, we'll have to wait for solid facts.