Are you using a Mac? I seem to be seeing a lot of Mac use posting they have display problem in Photoshop CC 2018 after the latest update 19.1.
Cancel "Preferences> Performance>Use Graphics Processor" option, back to normal.
Graphics Processor: NVIDIA GeForce GTX 650
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But now you do not have some CC features like 3D, Liquify, Rotate tool etc these require the use of your GPU. You may want to try some of the newer or Older Nvidia Device drivers.