Spaniard United said:
CPU could need new paste
CPU heatsink could need to be dusted
Check your fans and make sure none of them stop working
Also, for the record, stock heatsink is weak. You can pick up a very good air cooler for $25-$35 (Cooler Master Hyper 212).
I am an idiot. I forgot to mention. My fan is running fine. The BIOS says it is running at 2000 rpm.