It would probably just freeze and crash. Even if it didn't do that, the performance would be so terrible that to say it would be unplayable would be a massive understatement.
It may not even start. If it starts, it would explode. If it doesn't explode the universe may collapse. So, yeah. Don't do that.
*scratches his balding scalp*, wouldn't that be kind of time machine or something then? Or maybe black hole, void of frames? Anti-framing device? Now that sounds something that might actually sell, have no idea what it would be though
Actually it would not explode, because all modern CPUs have thermal throttling, so when they start to heat, they slow down. Way down. I actually have a very old laptop with an intel atom, but I really don't feel like testing it.
Even if the CPU did not have any protection against overheating, they would not explode. It is physically impossible. What would happen is thermal damage, a horrible burning smell and possibly a small fire (unlikely to spread outside the tower). If a battery massively overheats however, it CAN explode. Even a AAA can, as I know from experience when one exploded in my pocket (loud pop noise, followed by feeling some heat but it did not burn me).
I have a hunch that the game would first run 1-2 FPS on the smallest map and default car and then the processor would implode on itself.