Thanks, Fallingleaf! Would you have any luck with reverting to the 442.50 drivers? With the custom install, it should give you “Perform a clean installation” option.
Could you provide a DxDiag file? Copy and paste the text file created and paste it between two ~~~ like so:
~~~
DxDiag Here
~~~
If you have issues pasting here, use Pastebin and post the end of the link. (ie. 123456 for pastebin.com/123456)