I think they will trash the dual core 6600 until they improve their engine,
if you see atm.. they're imitating all the technology 3dfx used.
first the SLI mode, wich linked 2 voodoo 1 or voodoo banshee togueters...
Voodoo 2 was a new card, then the voodoo 2 banshee came was a similar as the dual core 6600 ( voodoo 2 banshee had 2x voodoo2 vpus )
the voodoo 2 wanst very good, because it didnt had a 2d aceleration and it didnt sold very good, but they improved the technology in voodoo3 ( wich If i remember correctly, had 2x voodoo2 vpus and a 2d aceleration chip. and it was preety popular )
My recomendation is wait until they fix their errors, Nvidia lately has adding too much "technology jumps" that they cant see their own errors ( like the slow card and monster vpu on the 5500 series.. )
myself im an Ati fan since I trashed my geforce 2 MX 400 wich gave me more bugs than good playing .. and im happily standing with a RADEON9800 pro..
---------
and If I remember correctly, Nvidia as nothing to do with the dual core proyect atm, since its gigabyte's product ( ie, until nvidia oficially releases the dual core videocard , I dont think they will do good drivers ) so you have to use the gigabyte's drivers..
thats my 2 cents
end of edit
----------