Notebook Boot and Lockup

Recently my laptop has started auto-hibernating due to what event viewer is calling "The system was hibernated due to a critical thermal event." I downloaded a temperature monitor to see what temps the cpu and gpu were reaching and the temps of cpu and gpu were 80 and 70 C respectively, and it had previously logged higher temperatures without it auto hibernating previously. It only reaches these temperatures when in-game but as that is the primary use for this laptop it is a huge problem, especially for online games. I have never previously had this problem until recently on the same games/programs. I recently updated the BIOS to the latest availble right before this occured and can't help be suspicious it is causing my problem, but I can't downgrade it or adjust auto hibernate temps in BIOS, I tried both several times. I now suspect either the thermal paste on the cpu may have degraded enough to cause this or it is an issue with the current BIOS version for my laptop (F. 08). Any other suggestions would be very greatly appreciated.