If you have a lot of texts built up deleting those can help a lot more than you would think. I think the messages get stored in ram if you've recently opened the texting app or something
Root your Evo and uninstall all unwated apps using Uninstaller for Root then download History Eraser, CacheMate for Root, and aCCleaner from the market.
I am telling you what.. I was wondering for the last month what was making my evo so damn sluggish.. I just used the advice on this site, and deleted all my text messages and this machine is ultra fast now.. that is insane,.... you think maybe since texting is next to talking to someone that they wouldn't store messages in their ram.. WOW thank you!!
Root your Evo and uninstall all unwated apps using Uninstaller for Root then download History Eraser, CacheMate for Root, and aCCleaner from the market.