I had someone ask me how I can identify my large lists in my environment. I said that they should identify large lists that have a large number of returned items in a view. Remember its the view that is kililng your performance not the large list itself. So here you go:
get-spsite -identity "URL " | Get-SPWeb | Foreach-Object {$_.Lists} | ? {$_.ItemCount -gt 2000} | foreach-object {$_.Views} | ? {$_.RowLimit -gt 100} | ft ParentList, ServerRelativeURL
# You need to change the URL portion (format: http://url)
You can also modify this to spit it out to a txt file.
Thanks
Manny Acevedo (PFE)