I see you guys have (naturally in good faith) removed my original post about problems I had with PoE. It was a bit [sneaky](https://www.youtube.com/watch?v=yWoBmdfS0d8), but is ok, I don't care.

Anyway, I found the culprit and for benefit of those in similar position I've decided to post it for someone else to find.

Symptoms:
- regular crashes, typically associated with CPU fans whirring up (but not always)
- replacing thermal paste (on GPU and CPU) helps a bit, but not much
- replacing GPU helps a bit, but not entirely
- problem seem to associate with increased temp
- if you dig in related PoE dumps (if you were lucky and dump was generated) -- you typically see some XXXBlt() function on call stack -- something moves large memory block somewhere

Solution:
- remove memory overclocking -- go to BIOS and reset memory timing to factory settings

Notes:
- I overclocked my memory (4x4Gb of Sumsung MV-3V4G3D/US) long ago (5 years?) and forgot about it
- I ran every memory test I could imagine -- everything checks out
- Only two games ever gave me problems -- Witcher 3 (a bit) and PoE (a lot)
- I imagine DMA transfer used by GPU to move data to/from main memory is much more sensitive to memory timings (than CPU) -- that is why memory tests (that use CPU to hammer your memory banks) didn't pick any problems
- ... but for some reason PoE engine (Unity?) hammers that DMA mechanism pretty hard (why it moves that data back and forth so often? looks like a quality issue to me -- my card has 6Gb memory, enough to put entire game there) and eventually triggers the issue

Anyways, problem identified and solved -- happy end. :)