CooLDBA (2/10/2015)
That's the reason it is good practice to do it on Development first. Test the Service Pack then apply to Production.
I've updated 5 servers from RTM to SP3 in the last month, and there has been performance degradation. I would say there has been improvement, but there were several other changes along with patching that may give patching undue credit. Chief among them was upgrading ISV software to a much newer version.
So, in my case, it didn't hurt anything 🙂