This saved me on the steam forums.
I tried all the config settings and the rage ati drivers and I still had HORRIBLE texture pop in.
But after I put this dll in my rage folder the pop in was gone and it worked wonderfully.
http://www.mediafire.com/?u8153rflr4y7war
Now the game runs extremely fluid on my 4890 with this in my config.
vt_pageimagesizeuniquediffuseonly2 8192
vt_pageimagesizeuniquediffuseonly 8192
vt_pageimagesizeunique 8192
vt_pageimagesizevmtr 8192
vt_restart
vt_maxaniso 4
image_anisotropy 4
and +vt_maxPPF 16 in my shortcut.
I also added the > c:/Users/"myname"/AppData/Local/id software/rage < folders so that the game would store its cache. like I found on youtube
http://www.youtube.com/watch?v=3ryK2PErQQc
It runs and looks great now imo.
I'm using 8xAA at 1920 x 1080
My specs are
Q6600 @ 3,2ghz
4GB's of ram
4890 1GB ram