Here are my History & Cache settings:
Tall and Thin
Big and Flat
Cache Tile Size 1024
I must admit that with the exception of History, I don't have a clue about what the other settings mean or do?!
But, if you can advice me in a way to improve performance, I would be grateful!
I get the brush lag (Mac OS X, CS5) in PS 5.1 but instantly when I start using it.
Until I figured out a simple "fix" that seems to work. I don't know if it will help you but here's what I do:
Save the image you are working in.
Resize the image to 600px.
Then Edit/Undo the resize.
For some reason, this has worked for me.
After the resize undo, I can continue working on the image with no lag.