Just tested the exp for some hours.
first few hours were fine, no low fps issues (exept for a 5 sec framedrop).
later i had the low polygon/low fps issue, but got rid of it by setting vidoe memory to 256mb and back to auto (day.exe used between 3 and 3.3gb memory according to the task manager)
thigs were fine for the next hour until the game crashed with that application error, without prior laggs

i had -dologs parameter enabled, so you will have some nice logs that will hopefully help pinpointing the cause
also bidmp files are attached {F31170}