Hi ive autoexeced this lot into my D3 batch folder and its really upped my FPS well at least its allowed me to use full AA/AF at high qual and 2/6 at ultra qual.
ive had a nightmare of a time with my 6800U but things are smoothing out
it is clocked at 450/1200 on a volt modded bios tho. hope anyone finds this helps 
also allows recording of demos with F10 and instant consol with the key below esc, you may wanna insert "//" in front of the mem usage lines as they take up a lot of the screen. also removing the "//" from befor nigtmare enable allows ultra hard mode, also theres a line for viewing the speaker outputs, to check u are really gettin surround sound
other than that a few commands like playDemo xxxxx.demo allows demos to be played at original FPS rather than lightning fast timedemo speeds, thats all i know so far, apologies if this has already all been done 
Az
Code:
//tweaks for d3 on a geforce 6800 Ultra extreme
set image_downSizeBumpLimit "1024" //1024 for 256mb gfx. 512 for 128mb gfx. 256 for 64mb gfx
set image_downSizeBump "1" //enables above
//Originally the above was set to 256, as if I had a 64mb card. What I believe it does is decide how large in pixels the bump map textures should be on screen. Without a performance hit I was able to use 1024 with a 256mb card. You can also try -
set image_downSizeLimit "1024" //1024 for 256 cards. 512 for 128mb gfx. 256 for 64mb gfx
set image_downSize "1" //use to enable above
set com_showFPS "1" //display current FPS in corner of screen
set com_allowConsole "1" //tilde key only for console *
//set g_nightmare "1" //enables highest skill level for the real hardcore
set com_showMemoryUsage "1" //displays current memory usage, interesting during section transitions
//set s_showLevelMeter "1" //display sound level meter for each speaker
// Record Demo - start & stop with F10 //
set startrec "recordDemo; set demorec vstr stoprec"
set stoprec "stopRecording; set demorec vstr startrec"
set demorec "vstr startrec"
bind F10 vstr demorec
ive had a nightmare of a time with my 6800U but things are smoothing out
also allows recording of demos with F10 and instant consol with the key below esc, you may wanna insert "//" in front of the mem usage lines as they take up a lot of the screen. also removing the "//" from befor nigtmare enable allows ultra hard mode, also theres a line for viewing the speaker outputs, to check u are really gettin surround sound
Az