Sounds like a display compositing issue... Are you running Windows?
If so, your display driver may need updating to correct problems with new graphics features Photoshop CC (2014) needs. Visit the web site of the maker of your video card to ensure you've got their latest display driver for your hardware and operating system.
Also, there are settings in the Preferences - Performance - Advanced Settings section that change the way Photoshop uses the GPU, and trying alternate settings there may help with the problem. Make sure to quit and restart Photoshop after making any changes there.
Good luck.
-Noel