Hi Guys, if it helps anybody...got the rig running at same speeds but only using 850W now - thats 1/3 decrease - £30-35

Those 2 cards that are playing up i have running stock clock (otherwise a crash) but only 650Mv on core and memory

Others are running at 850MV core and 900MV memory 1100Mhz/2100MHz

Used the overdriveNtool for the tweaking.

Nvidia cards i have at 80% power target (Msi Burner) and 500MHZ mem OC.