The b250m is an 1151 intel board but the nomenclature looks like amd. I still think the problem is the cpu having a less than optimal cooler on it has caused cpu dmg. Dunno if it's been fully stressed yet. A screen freeze is a cpu stop and that's what they do when thermally dmg'd. It can happen if the cpu is under volted but the circumstances are that the pc has been running ok for 16 months until now with the 160w cooler on the 180w cpu, albeit with some good airflow, and the question of how warm we're getting under load hasn't yet been fully answered.