Those NV36 clocks are wrong. There are two versions, AFAIK - ~400/325MHz TSOP (5700) and ~500/425MHz BGA (5700 Ultra). It has a 256-bit memory interface but a question remains as to whether it will have the fillrate to make use of it. If it really is "half an NV35" then probably not - even if they introduce higher FSAA modes that will make use of the bandwidth, they'd probably be too slow to be useable anyway. Shader speed is going to be critical as well - particularly PS where the current part is absolutely trounced by ATi offerings. I suspect ATi may have the upperhand in HL2 (shader-limited) and nV in Doom3 (stencil op/bandwidth-limited).
Not sure whether you'd want to wait until October for it though, Q-Bert.