hi sir thanks for the reply i got 6 Sapphire Radeon HD 5870 1GB 256bit GDDR5 v2 and i just want to know from the users of v2 if there's a difference between the reference card and the sapphire 5870 v2?

what will i overclock? and im confused what's the undervolting gpu? what if i use 1x6 what pci-e risers i will use? example i have 16x 8x 1x(4) pci-e slots on my board

thanks a lot