TBH I have noticed no performance drops. However, I have had BSODs, freezing and reboots as well as two programs dying and refusing to run any more.
The other morning my PC would not shut down. I could not CTRL ALT DEL etc so I had to force shut down holding the power button. Then it refused to boot for about 30 mins.
Right old PITA this stuff. Won't be updating my new PC at all.