4vCPU SQL VM - add another just for OS?

[RFTadmins]

Good day all.

We had an issue today that cause a DB server (4 CPU SQL VM) to run at 100% CPU load.  I was able to get onto the RDP session but then it was too hard to navigate around due to slow response.  I was thinking of adding a 5th CPU and set the SQL affinity to only use 4 of the 5 CPU and reserve the 5th for the OS.  Thinking that if something like this happens again, I can still get to my troubleshooting tools.  What’s your thoughts on this?  Thanks in advance.

[weinstein5]

Welcome to the Community - I would be leery of setting CPU affinity - Microsoft recommends it only special instances and this feature will be depreciated in later version of SQL - I would first find out why you had this spike and address that issues - If the load is increasing than I would consider adding additional processors