Dropped Computer Horrible Frame Rates

Hey there,
Unfortunatly i dropped my Computer out of a height of about 30cm on solid ground. The CPU-Cooler came of, but appart from that, there was no real damage visible. i reattached the cooler (without applying paste) and started up. Everything was fine, except when i started programms, that required high graphic performance, like newer games, my framerate was horrible. The Sound was running smoothly. I checked my Sytem performance and RAM and CPU was at decent numbers. To be honest i haven't checked it in Detail before so i can't tell which numbers have changed. I noticed that the Disk performance was constantly at 100%. Im using a Radeon R9 200. Appart from the frame issues i did not find anything out of the ordinary.

Do you have any ideas on which part of the Computer might be damaged? Im not a native speaker, so don't be offended by my grammar.
Thank you