I recently re-installed CS6 on my iMac and how I am having a problem in Photoshop. Random pixelated patterns in grey, black and other colours flicker all over the canvas whenever I try to do anything, such as using any tool or even zooming in/out.
The "patterns" are made up of little rectangles and appear all over the canvas:
Additionally, when I have anything on the canvas selected, the flickering extends over the grey background area as well:
This only seems to happen when I make a selection, not when using tools, zooming etc. It's hard get a screenshot how annoying this is, but it is flickering very rapidly across the whole screen, somtimes large chunks as shown above, sometimes very small ones.
I have had Photshop installed on this computer for a year with no issues.Any ideas what may have caused this or how to fix it? I have googled but all I can find is an issue relating to a flickering background in Windows 8. Any advice would be much appreciated - I am a professional web designer and this is driving me crazy! May be worth mentioning that I am not having any issues in Illustrator.
Thanks in advance.