This seems to be a defective processor, but in order to determine that for sure, I would suggest testing the processor on a 2nd known working and compatible motherboard, this way you will be able to determine if the issue actually follows the processor.
If you do not have a spare motherboard to test with, you can test the processor on a friend’s motherboard or by taking the processor to a local computer store to be tested.
Thanks for the answer. I hoped that there were some reliable softwares for checking if the processor is working normally. Even in a local store, it is not obvious that they would have the patience to wait until the processor stops working sindc the freezes are occuring randomly..
I think that the processor is good, there was a problem because 1 year ago I tried to add another soundcard but I realised a bit too late that there was no available slot. But I think I moved something during the operation, and I have now apparently fixed it.