The Evo does NOT run slow on ics. ICS on the evo 4g is blazingly fast.
Twilightkid, everyone is being very nice to you instead of hitting you with the facts.
The facts are that you need to upgrade your rom. When you do, you need to do a FULL WIPE of the phone AND the sd card. Partition it, and give MikG 3.0 a try. It is also extremely fast.
My Evo runs incredibly fast. You're just doin it rong. Moreover, ICS will run fantastically on any halfway decent phone that you stick it on.
In case you are completely unaware, there is still only one phone that can actually compare with the Evo4G. Phones running dual and quad cores are useless at this present moment because none of the roms or apps take advantage of the other cores yet.
This should all change when htc announces the EDGE and the Zeta.