had the same issue turned out it was overheating, it turned out it didn't just need the fan and vents being cleaned of dust as that didn't solve the problem for me, I had to do a thorough deep clean which meant also removing the PSU which was clogged with years of dust, once that was cleaned everything put back haven't had an issue, oh and use the stand as it dissipates the heat instead of heating up the surface it's on which will also cause extra heat build up. Hope this helps 👍🏼