Thanks a lot. All your tips have been really helpful. I now know what REISUB is 
and I just reconfigured grub and tested it. Works. However, when my system freezes normally the keyboard becomes totally unresponsive (caps lock for example does not work and no lights), so I am curious to see if REISUB will work. I have read reddit forums where numerous people have had random freezes with NVIDIA drivers where the keyboard also becomes unresponsive so I pretty sure it is a driver issue…