I'm also getting (seemingly) random freezes while playing BOW, where everything crashes, and I have to reset my computer. The sound buzzes, and the screen turns into what looks like corduroy (solid colour, covered in vertical lines).
This has only been happening since I installed the latest patch update, I've had no issues at all previously.
It happens after about 5 minutes of play, no matter what I'm doing - fighting, exploring, or even paused in the menu.
I'm on Windows7, with an ATI Radeon R9 270X. I tried updating the drivers, and it made no difference. I've also tried reverifying the game files in GOG. I don't have Forgotten Sanctum installed.
Output_log is here.