From what Buildzoid wrote on his blog about it, the memory should benefit from core voltage.
I didn't test myself yet but I will try. I also don't know the core to memory clock ratio on the card yet. Apparently some have a golden ratio where memory won't be stable but can be at higher clocks because of core clock.
I hope I will be able to test it soon, also card might be trash on cold, it isn't a golden card either, I've seen some going higher on water cooling, but temperature seems to also be important as the second card I got can run 1200MHz core when it's under 60 degrees, when it gets over it can't go beyond 1125MHz.