Hi I have just bought an ati 4670 1gb powercolor. In order to maximize the power efficiency I wanted twek the bios with RBE. Prior to do that I wanted to test with ati tray tool frequency and voltage to apply later with RBE to the bios. The fact is that ATT can't really change the voltage. Even downvolting from 1.2v to 0.9v keeping the 3d frequency of 750mhz the card is stable (which should be impossible such downvolt). Moreover even with such as low voltage the temperature under stress don't change, so my guess is ATT doesn't have any effect on this card regarding the voltage. Can RBE succeed where ATT failed? All the voltage ATT allowed me to set are the same showed under RBE. I have basically tried all the steps. I must admit that what makes me pessimistic is that all the default voltage for this card (boot,2d,uvd,3d) are 1.2v..