Dunno about the new cards, the new afterburner limited me to 1.35 Volts. I use riva with config and Volterra plugin to jam up to 1.45v through my 4890

, then Afterburner for OCing.
Oh and when ever I make an adjustment to Core/mem I have to adjust fan speed too or it drops back to "stock" (still reads whatever I had set it to previously)