they have improved it alot over 4.1, my fps is now mostly steady capped around 76, instead of an unsteady capped at 47 
from around and about I get the impression the 3.7s are the “fastest”, but I’ve only tried 3.9 (for like a day), 4.1, 4.1 omegas and these 4.2s.
I think ET is less CPU bound than RTCW, and especially Q3, but I’m thinking if you have a fast card it’s probably more the CPU holding back FPS. For a quick test you can try running a timedemo at 800x600, then doing it again at 1024x768 or whatever higher res (maybe adding a fair bit of FSAA & Aniso for a 3rd run). If FPS stays roughly constant it’s probably CPU bound, if they drop signficiantly at the higher res then it’s likely to be the video card / drivers.
ToeD did you remember to install your motherboard chipset drivers? Thats a common thing to forget on a OS reinstall that leads to a drop in performance for, well, about everything.