SQl server 2008R2 Performance issue after SP3 update We have recently applied SP3 KB2979597 and Security Update Patch KB4057113 on Sql server 2008R2 but after that our couple stored procedures runs slow, it's taking almost 4 to 5 hours, but normally it was running under 5 minutes.
Any one has idea that SP update causing any issue?
We have applied earlier same SP and security patch on test server and we didn't have any issue.
Any quick guidance really appreciate.
Thanks for your help!
Any one has idea that SP update causing any issue?

The security KB (KB4057113) is for the spectre / meltdown group of CPU security attacks.  They have been known to cause some performance slowdowns, but nothing that drastic.  Still, I thought it would be worth mentioning in an answer.
You may want to install the latest operating system patches to make sure you have the latest and greatest changes on that side of things (the initial patches addressed the security flaw, while some subsequent ones addressed performance).
See this Q&amp;A on the site for more information on what you need to do:
As a SQL Server DBA, what do I need to know about the meltdown/spectre vulnerabilities?
Other than that, you should get execution plans for the slow procs from before and after the update, and compare them.  The more likely culprit is a plan change, which could be based on a number of factors (often unrelated to the update, like parameter sniffing).  Feel free to share them here to get specific help with them.