FCPX Trashing Preferences

Good Morning;

FCPX runs slow on my 27" iMac with 16GB of ram. My first action is to trash preferences. I went to home/library/preferences to trash:
com.apple.FinalCut.LSSharedFileList.plist & com.apple.FinalCut.plist.
There currently is 135 com.apple.FinalCut.plist.0t0Ecvw with various extensions.

Do I trash them all and is this normal?

Thanks

Kent