IntroductionWhile the launch of NVIDIA's GeForce 6-series of GPUs was way back in April, it's not been the easiest of rides for them, or indeed ATI soon after, to get their new GPU series to retail. That only 6800 Ultra boards were available to most European websites in April is testament to that fact.
So it took us a while to snag the other pair of AGP reference boards, based on the 6-series. The plain 6800, usually referred to as the non-Ultra, sits at the bottom of their new range, while the 6800 GT sits between the 6800 and the 6800 Ultra.
It therefore makes sense to see what defines each board.
Currently, NVIDIA state that a 6800 Ultra is a full four quad NV40 (AGP part) running between 400 and 425MHz, with 256MB of GDDR3 memory running between 1100 and 1200MHz on a 256-bit memory bus, with a pair of DVI ports. Any 6-series board that meets those specs is a 6800 Ultra. Any board that comes clocked higher is able to be called an Ultra, according to NVIDIA's marketing specs, but the GPU shipped to them by NVIDIA after sale is only warrantied up to 425MHz.
The GT is defined as a full four-quad NV40 (again, on AGP), running between 325MHz and 350MHz, with 256MB of GDDR3 memory running at up to 1000MHz on a 256-bit memory bus, with either dual-DVI, or DVI and VGA. Meet those specs, call your board a GT according to NVIDIA's marketing specs. Anything over that spec is a partner-defined board that may or may not be allowed the GT moniker, since it potentially impinges on the basic Ultra spec, depending on the DVI port configuration.
Finally, the plain 6800 is defined as a three-quad NV40 (AGP), running at 335MHz, with 128MB of DDR memory running at up to 700MHz on a 256-bit memory bus, with either dual-DVI or DVI and VGA, although more likely the latter. Meet those specs, call it a 6800, but not a GT or Ultra. Anything over those clocks is undefined.
I'll sum those up in a handy table.