Hi, i think you can close this ticket.
Problem seems to be solved for me.
The issue was that my GPU has 1280 MB vram, and the video memory setting in Dayz was for some reason set to 2048 MB.
I've turned it back to Auto and now it seems to be working fine.
Played for 4-5 hours now without any crash, and the RAM usage seems to stay on normal levels.
Seems strange to me that the RAM usage kept going up because of my video memory setting.
Maybe this "solution" can help others.
Cheers.