i will keep this as short as i can. i have 2 6950's. asus cu II/club 3D both non referance. i have to use msi afterburner for the club 3D card to adjust voltage. im using ASUS gpu tweek for the cu II card to adjust voltage on that. my problem is i cant get past 840MHz core in xfire,every time i go above it locks or BSOD's on me. the cards are fine at 840MHz in game and running kombuster run X-score. i cannot get them to work above this with ANY amount of safe voltage. both cards oc WAY higher than this on there own. i tryed the regedit trick to fix msi but it has not worked. im wondering are the oc tools conflicting with each other? also im running old drivers as the new ones will not work for me. driver set(8.96 i think). i have no bios mod on the cards although i did have the asus flashed for the shaders but put it back as i couldnt flash the other card. the rig. ANTEC high current psu. 750W intel i5 2500k@4,3GHz ASUS P8P67-LE 8gb's corsair vengenance win7 64bit. i have searched high and low for a fix and i cant find anything similar even! you guys are my last hope!