Photoshop CC 2018 is working fine when loading JPEG files or previous PSD fiiles. BUT while opening RAW files in Camera RAW and opening a Smart Object in the Camera RAW filter and allowing them to be worked on, in both cases, on re-importing to Photoshop, the program freezes, and the only way out is via closing the program with the Task manger. (Working in Windows 8.1) Similarly, Adobe Bridge freezes after opening a file in Camera RAW and then trying to use the file or open it elsewhere. No problems before upgrading to the 2018 version.
In Preferences there are two areas where you can disable the GPU. I had previously tried disabling the GPU in the Photoshop preferences, but it had no effect – and I didn’t really want to do that because I wanted the benefit of it in Photoshop. You can still leave the GPU enabled in the main Photoshop performance settings.
Go to Preferences>Camera Raw. At the bottom of that window there is a box headed Performance where you can enable/disable Graphics Processor. Disable it. Problem solved!