hey i have the same board well mine is the p67 version, i was wondering does your chipset get hot? i have my 6950's and 26k watercooled but my chipset gets mega hot, im 99% sure its because im using the nf200 and its known to get toasty, just wondering if while playing a game you can pause it and just put your hand on all three chipset heatsinks around the cpu to see if there hot? if not then i will just stick my cards in the same pcie slots as you because the heat is incredible, will also save mee £100+ on a moboblock.
i also have both molex connecters on the board plugged in, they say it gives extra power to the pcie lanes which help keep gpu's stable especially when ocing them, and if you have a oc'd cpu it takes some strain off the 24pin and 8pin connecters