Aero effects turns off after overclocking

I had the same issue with AMD Overdrive inside Catalyst Control Center (but not with AMD Overdrive standalone app) with CPU Overdrive option.
After I set a higher clock, aero got disabled and performance degraded.

Today I found that I had to adjust the clock multiplier in BIOS setup to match the clock rates set in Overdrive.
Now Aero got back and performance increased as expected.

Another thing I found is that if I set clock multiplier only in BIOS, but not in CCC, the CPU clock rate increase only when using single core applications, or in disabled cool n quiet mode. Since I need cool n quiet, this is unacceptable for me.

This is releated to Turbo Core technology.
In my example with my AMD FX-8320: Battlefield 3 uses only 4 cores, so my CPU clocks at 3.5Ghz when playing. No matter if I set stock (3.5ghz) or increased (3.9ghz) clocks in the bios. This clock is pre-set somehow for 4 core processing. (higher for 2 cores, lower for 8 cores. This is normal AMD behaviour)
Since I set 3900Mhz in CCC and the same in the BIOS I could solve this issue and my CPU runs 3.9ghz while playing, and Aero is also working. Also Cool'n'Quiet also works so power consumption is normal all the time.

I have the same problem, this happens if I overclock NB on FX processor.


bcdedit /set useplatformclock true command helps, but it degrades performance