Try to use a SSD to save the drivers and updates for it,     1) You may have downloaded the wrong drivers when updates come around i.e you need gtx drivers, so do not use the rtx 1's.  2. You are not cleaning the ssd Completely of the drivers from OLDER GPUs meaning that corrupt files are probably mixed in with the new files. So Do a complete sweep of all the GPU drives and files, even nvidia geforce then try drives from Evga or nvidia online.  That usually works! Hopefully that helps U!  Good Luck

redfufu
I use an SSD and I have done that, downloaded the GTX driver straight from EVGA. Also used DDU to clean old driver

Have you tested the GPU in another system? How is your power stability where you are? Do you use a UPS?  That looks like memory failing on the GPU. If you under clock the memory using Afterburner, is the GPU more stable?

redfufu
I don't have another system to test it in. The power has been stable but I'm not on a UPS. I have an old 760 that I keep around because of this issue and everything that can run on that card runs fine.

A 760 uses a lot less power than a 1080 Ti.  Can't rule out a PSU with 3 GPU's going bad. The other question, if you down clock the memory, it is more stable?

Underclocking had no effect still crashed. I have noticed a pattern that has happened with all 3 cards. Warthunder tends to be the game that crashes first, then other games crash more and more often after that until with the last 2 cards when the computer tries to reboot the card crashes on reboot and gets stuck in a boot loop. Like right now Warthunder is a guaranteed crash and so is DOOM, Minion masters just started crashing it the other day after a week of it running fine while warthunder would crash it but yet I can play a game like Men of War assault squad 2 with no issue at least for now