I have a content search web part on my page that is querying a blog list and shows 4 results from it.  It queries the post itself and any picture attached to it and displays it.  The page takes about 20 seconds to load and then will be extremely quick after that for another 20-30 minutes and then it's slow again the first time it's accessed after that.  I have narrowed the problem down to this web part but can't figure out why it's happening.  

Has anyone seen this before?  I have also tried using both static and continuous crawls for search and the same thing happens.  

Are you using an OOB template or your own template? Also, check if there is any timer job or any other process that is running every 30 minutes. Maybe when the search crawl is impacting your performance?

We had a template created for us by a group of consultants and unfortunately I'm not familiar enough with it to know if it might be causing the slowness.  It looks to be an HTML and .js file.  

HTML and JS are the OOB files for any display template. Although, I highly doubt it is causing the issue, since the performance is OK sometimes and it's not always slow, but I would definitely check what properties it is loading. Sometimes it will have a study impact on the performance.

How often is your search crawling content?
Is your Search crawl on the same server as WFE?
What are your server specs?

Mike

Thanks for the help Mike, it turns out another web part on the page from a third party vendor was causing the issue.