sp_BlitzCache slow results on @SortOrder='cpu'
The most likely reason for this is a very large execution plan in the cache that doesn't show up in other sort orders. That can certainly hold things up when we hit the RelOp section of the XML.

You can use the @SkipAnalysis parameter, and set it to 1. This will skip all the XML analysis, but it will get you results. You'll want to use @ExpertMode to get the SqlHandle and QueryHash for the big plan that's holding things up.

EXEC sp_BlitzCache @ExpertMode = 1, @SkipAnalysis = 1


When you figure out which plan it is, you can use the @IgnoreSqlHandles or @IgnoreQueryHashes to skip over that plan in the cache in the future. 

EXEC sp_BlitzCache @IgnoreQueryHashes ='', @IgnoreSqlHandles = ''


Hope this helps!