Have you replaced the AT&T ROM with a cooked one and got rid of the AT&T Bloatware? I notice my phone was a little slow when I played with it for 10 to 20 minutes to make sure it was working properly before flashing a decent ROM. Check this link out:
Raphael ROM development - xda-developers. I prefer NATF's HTC Fuze and Touch Pro V2.3, but V 3.0 should be out this weekend. Oh and there is most likely a fix for your issue in one of the forums if you have already flashed a new ROM.