I see nobody has asked the critical question, what operating system are you using?
Assuming it is windows, which version?
If using Windows 10 then personally I would follow this advice.
If you are using Windows 7 then I would follow this advice, with one change, I would take the old card out after the clean and shut down and before the once you've rebooted, unless you like fan cut fingers, possible sparks and a most certain windows crash that will quite possibly lead to a reinstall.![]()
If you are running Win 10 you definitely want to run DDU when switching between AMD and NVidia.
I had Win10 wanting to download AMD stuff the other week when the PC was running some GTX 1080s. I think if I had run DDU after removing the drivers I would not have had the problem.
