Hi.I want to overclock my Sapphire HD 7950 3GB with Trixx but i dont know how much should i change the VDDC number for a stable status with GPU clock @ 950 Mhz and a higher Memory clock. Btw my stock GPU clock is 810 Mhz and Memory clock at 1250 Mhz. I got a ASUS P8Z77-V with a Core i5 3570k @ 4.5 Ghz and AcBel 660 watt PSU in my rig.Any famous oc numbers for this card ?