Your system did a "safe shutdown" via the bios. It got too hot and the "overtemp" feature kicked-in, especially if beeped like crazy before the shutdown. The overtemp is a cause for concern and prolonged operation, especially with a AMD cpu will eventually breakdown or fail outright. You need to verify the system fans are working 100%. if you've recently added anything it may have been the last straw sorta speak and the result what you're experiencing. Review the bios setting and verify the FSB is what it should be as it seems the FSB got hosed, reset it. usually, in heat build-up, open the case, place a household fan to blow into case and see if things settle, if they do then find out the heat build-up cause. As the others mentioned, a power supply or intermit fan can be the cause. Also, reroute the cables, wire harnesses to better the "airflow" and if possible add an extra case fan to help exhaust the heat build-up. You should also look into a better cpu fan as "gaming" will place extra stress on the system as its demands put the system into extreme overdrive if all the goodies are enabled. Last, evrify the cpu is what you paid for and not "gimicked" as a higher rated cpu. This maybe all mute if damage is started and will fail later, but if any warranty, use it. 
good luck -----Willy