Thank you for joining the Intel Communities.
It would be really useful for us to have the Intel SSU report from your system in order to get more detailed information about your system in order to assist you as Ronin was saying.
Additionally, please let us know if something besides changing the CPU affected the systems performance.
Something else that you can do is to run a system check, this is to find possible bad files within Windows*.
In case you have issues providing us with the SSU report, here some instructions:
-Download the utility
-Scan your system with the utility
-Export the report (hit next and then save) and attach it to your answer with the advanced editor option (reply button and then check upper right corner)
Please let me know how it goes.