Just installed 10.5 for my 5770, and my default 2D (no video acceleration) went from 157 core 300 memory (with 10.4) to 400 core and 1200 memory. I uninstalled 10.5 and went back to 10.4, and again am running at cool 157/300 rates on the desktop. 10.5 broke?
Yes. After uninstalling CCC 10.4 properly and installing CCC 10.5, I have default idle clocks of 157 / 300 ( core / memory ). This time CCC 10.5 is running properly. Since the day CCC 10.5 was released and I installed it, it has not given me any "Ati Radeon Family display driver stopped responding and has successfully recovered" warning messages till now. If it does as with all previous CCC versions, I will increase the idle (2D) clocks with a profile. In that case, my sweet spot for idle clocks is 200 / 400 MHz.
My cards are usually 157/300 after 10.5 but on occasion I've seen my 2nd card sits at 400/900. It was fine until for some reason yesterday it went back up to those clocks. In the RBE bios editor I noticed that the "profile setting" that activates those speeds is called "UVD" but I don't know what it means.