To open and edit Raw files in Photoshop no Raw driver from camera is needed.
The problem likely arises from an outdated (old) video card driver for Windows 8.1
Go to the video card manufacturer web site and download the latest driver released for Windows 8.1
Have you checked you monitor color profile.
Unchecking GPU in Camera Raw preferences (not PS preferences) fixes this. An updated driver should, but no guarantees that this particular bug is fixed.
Generally there's no need to have GPU enabled in ACR, except if you have a 4K / 5K monitor. Then it supposedly speeds up screen redraw. With a standard monitor it just adds overhead and may actually slow things down.
Thank you, this has fixed the problem.
The files are .arw format. Please don't edit things to raw when the file type is what I stated.