I'm experiencing extensive brush lag while using CS6, almost since day one.
I use rapid brush strokes and every four or five strokes I get a lag spike. With my drawing technique, this renders Photoshop almost unusable.

I'm using an iMac Mid 2011, 3.1GHz Intel i5, 8gb memory, AMD Radeon HD6970M 1024MB, with OS X 10.8.2, drawing on an Intuos5.
As far as I'm aware, it should not lag at all on this machine. Hell, it chews up huge HD video files in post production with no trouble, it should not lag when I'm doing a 1000x750 pixel sketch.

Here are the things that I have tried that have had no effect on this problem:

- Updated Intuos to latest drivers.
- Tried turning off "Use Graphics Processor" in PS
- Reduced "History States" count
- Switched "Drawing Mode" to "Basic"
- Tried turning on and off all of the "Advanced Graphics Processor Settings"
- Worked in smaller file sizes.
- Reinstalled PS.
- Reinstalled the whole goddamn OS.

The problem doesn't go away.
Does anyone else have this issue and does anyone maybe have a solution?

The easiest fix would probably be to go back to CS5 or 5.5 but I would like to try and fix this - if at all possible.

Thanks all.