Months ago I changed my processor (FX-8350) frequency from 4000MHz to 3600MHz through the AMD Catalyst Control Center because I was having problems with the temperatures but it runs particularly bad and I would like to try it again at full-speed... but I can't find the Catalyst Control Center, I find something similar but it only has graphic settings (and it's called Radeon). How can I revert it back to 4000MHz now? Looking the AMD Overdrive I can see it keeps being at 36000MHz.
You should be able to go into your mobo BIOS and set the CPU to "auto" detect, save changes and reboot. You can also manually set the CPU multiplier to "20", save and reboot to run the CPU @ 4 GHz. AOD does the same thing but the BIOS method is preferred vs. software making BIOS changes for you.