I just installed another GTX 580 Classified in my rig.   I now have dual SLI with 580 Classys..  It runs awesome, no complaints.   They're powered by the SuperNova 1300w G2.
 
But I did notice something odd and was curious if it's normal.   Both cards are stock speeds for now, no OC, switch is in on normal setting, lights are green. 
 
When my new classy run at max speed it's 1100 voltage. My original,  I think/thought perfectly functioning classy runs at max the voltage is 1130(pretty sure its always been that way) .   Is that normal? 
 
I tried running each card by itself and its the same thing, I also tried swapping pci-e slots, no luck.  When the cards idle down to 400 or 50mhz they are both at the same voltage, its just when the cards are at max when the voltages are different. 
 
Thanks for any advice!