7800gtx sli overclocking - 3dmark score does not rise

[deff_ins]

2x xfx 7800gtx voltmoded, stock 490/650
cooled with chilled water
both have indential bios (2d & 3d low power mode disabled, low timings, delta 50, temp. monitoring disabled)
both cards can reach 11k 3dmark05 with ~630/770 (1,8v core, 2,4v mem)
sli stock score - 14k 3dmark05 - it's ok i think
but overclocked sli score does rise only aboyt ~200 marks... wtf? first problem is with setting core clock (tryed latest atitool and rivatuner) sometimes only one card is overclocked, other dont want to set clock. sometimes one or another card drop their clock to stock due to unknown reason and i need to set it back with some 3d software running in backgraound.
it seems the problem is - i dont know how to overclock sli so... should i flash both cards with 630/700 voltmod enabled? it seems dangerous

oh, another thing... do i need one more psu for video cards...?

so any ideas are welcome gentlemans

sorry about my english

[EmineM]

I have a similar problem with mx 512 MB GTX's score doesnt seem to rise with more CPU freq and gpu core freq.

[deff_ins]

but thats with single card right? with single i dont have problems... i think so
main question is - how to force NOT to drop down core frequency in 2d mode?

[freecableguy]

are you OCing by flashing the BIOS or with RivaTuner/ATI Tool? you need to hard-code the cards with a BIOS flash in order to get a "real" overclock

[afireinside]

task manager>processes>end NVsvc32.exe

also with 81.95 or newer drivers if you open up the driver pannel under properties to change settings or watch temps the clocks will set back to stock. MM and I tested this. I ran a 120k AM3 then opened drivers to view temps and ran 105k.

[deff_ins]

yep... it looks thats the problem... using bios 600/770 score was ~15400 in 3dmark05... and that the only way? sad
how about setting for every card different core clock - will it work? because one of the cores is little weaker... can about 630, another 640.

[Dynasty]

but thats with single card right? with single i dont have problems... i think so
main question is - how to force NOT to drop down core frequency in 2d mode?

Enable perf. level forcing in power user/riva tuner,
then force constant perf. lvl > perf. 3D in driver-lvl hardware overclocking.