GeForce 8800 Ultra is a high-end GFX and the most powerful GPU of the GeForce 8000 Series, based on the 90nm variant of the first-shader unified architecture.
It's based on the G80 Core (same used on 8800 GTX) and offers 128 Shader Processing Units, 32 TMUs and 24 ROPs, on a 384-bit memory interface of GDDR3. The central unit runs at 612MHz and the memory clock operates 1080MHz. It will consume no more than 172 Watt.
It can be addressed as a further clocked GeForce 8800 GTX and is known to heat a lot. As the most powerful GPU in 2007, even today's modern demanding games can be played at medium or high settings smoothly. However, DirectX 11 based games aren't supported.