This is less than 640 maxmem, but with this ES I have can run 1m/pf all day 2620mhz but cant bench 32m over 2500mhz not exact in round within the first 4 loops.
This was at 620maxmem. I'll give 640 a shot next time.
Both install fine and show up in device manager. Same bios on each card....both show up in nvidia control panel, and it even allows me to select one of them for physics but no sli option. I'm dumb thanks.
Btw using latest whql driver xp x86
out of 1.23 1.24 1.25 and 1.28 chips
1.23 = 6.73ghz
1.24 = 6.65ghz
1.25 = 6.45ghz
1.28 = 6.37ghz
Seems like some batches just stop scaling with volts earlier. the 1.23 6.73ghz chip can do 6.58 at 1.68v but then eats volts up to 6.73ghz