Chances are you're experiencing a Windows 8 bug and/or a shortcoming in your display driver.
Some things to try:
Visit the web site of the maker of your video card and download/install their latest display driver for your OS and hardware. Recent driver releases from the major players have worked around this Windows 8 problem.
Go into your Preferences - Performance panel, click through the [Advanced Settings...] button, and try the other Drawing Mode settings (e.g., "Basic"). Make sure to close and restart Photoshop after changing things here so you're really testing the updated settings.
(A longshot) reset your Photoshop preferences to default: Press and hold Control -Shift -Alt simultaneously (or Command - Shift - Option if on a Mac) immediately upon cold-starting Photoshop. If you get the keys down quickly enough - and you have to be really quick - it will prompt you to confirm deletion of your current preferences, which will lead to the establishment of a fresh default set. If it does not prompt you, you haven't been quick enough to get the keys down.