Check your History States and Cache Levels in Preferences/Performance.
What values do you have?
Have you installed all the updates for Photoshop?
The only slowdown that I know of occurs if you change screen modes (with the 'f" key) a lot.
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!
Hi Chris, I do use the f key, but can this slow the system down?
Is this a known problem?
If purging the cache fixes the problem, then you at least have an idea of what to look at.
Using the "f" key to change the display mode a lot does cause a slowdown due to a combination of windowing/OS issues. Try the CS6 public beta (grab it quick) and see how that works.
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.