LM3S811 Eval Board Problem

I've been having a problem with the eval board lately. After about an hour or so, the data outputs from the GPIOs are not correctly talking to my large LCD. If I turn it off for 20 minutes then try it again, everything's ok. I think there may be some sort of thermal problem with the eval board. I've changed the LCD and get the same results. I don't have a logic analyzer available to actually check the pins.

Anyone else having this issue?

C@PPER