From the above description, it's difficult to point out anything particular at this point. As you mentioned, sensor showed a high temperature ( though not sure about 500 degree), so overheating might be an issue here. Following information may help us to better understand the problem:
1. Did you observe the issue earlier or just this time? Means, do you observe it frequently?
2. Is it related to any particular application or process that causes the problem?
3. After a hang, does a reboot make the system working again?
4. You tried with two performance setting. Any difference in observation?