All i can tell you is i keep an image(acronis true image) of my clean install of Win7 with no audio and video drivers for that very reason.
It takes like 6min to restore an image on my SSD.
So that might be something to consider since it is nice to have a clean image to fall back on when needed, and it comes in handy for testing.
As a matter of fact, I just restored my "clean install" before installing the 12.2's, so mine are installed as clean/bare as you can get.
I'm running dual 6950's, so i have no clue if your 4890 has anything to do with it.
I don't see why it would though but you never know.