I have spoke with some of the tech support mods of the forum associated with AcesHigh2 and in summation it goes like this:
The most current AMD drivers for 7XXX sometimes have artifacts(ing) issues with AH2. It could be possible to roll back the drivers and test whether it fixes problems.
Some have also said that AH2 only runs two cores and that having a really fast card is not necessarily required, but having a card that renders more stable and higher fidelity graphics would be better. Therefore, some of them, recommend Nvidia based cards.
Does this sound right? If so, then the 660 here should be the choice or have I misunderstood something?