I have this card too and I don't think 1.28v is safe because the pcb on this card is not made to take the extra voltage. I am even skeptical about running my card at 1.237v. The only time overvolting that high is really safe is with an msi card.
timil how does that card run with the 965 ? no such bottlenecks ? do you play bf3 if so what is your gpu usage and your Resolution.
my apologies kuziwk I know this is not related to what you ask