You say "cards"... Photoshop isn't great about using GPU capabilities of multiple graphics cards unless they're identical, and even then I wouldn't bet the farm on it...
There have also been some recent problems with ATI display driver installers not properly installing updates.
What cards do you have, and what drivers?
Have you tried the various different advanced modes (Basic, Normal, Advanced in the Performance preferences)? Keep in mind changes there should be followed by a close and restart of Photoshop before testing.
After your post I redouble checked everything. And it looks like having more than one card in my system is Photoshop's problem. While rechecking everything, I stumbled upon something I missed a couple of times:
6. If you are using more than one video adapter, remove the additional cards.
Multiple video adapters can cause problems with GPU-accelerated or enabled features in Photoshop. It's best to connect two (or more) monitors into one video adapter. If you have to use more than one video adapter, make sure that they are the same make and model. Otherwise, crashes and other problems can occur in Photoshop.
After disabling one of the cards, I have one screen less to look at, but Photoshop runs like a charm.
In other words, I found a workaround. I hate to keep disabling and enabling my card depending on what I want to do with my computer when it is not necessary. Is there a way of telling when Adobe has fixed an issue like that?
I doubt they're working very hard to "fix that issue" since people running multiple video cards are relatively uncommon.
You say you have one less screen to look at...
Understand that most modern video cards can run more than one monitor right from the same card. For example, an ATI Radeon HD 7850 - currently only about $200 - can run up to 4 monitors from one card. You may not need all that hardware in your system.