VIDEO_TDR_FAILURE (116) - Only ever when playing games.

Hi guys, I have read 25 pages back on this forum and countless threads but I have not been able to find a solution to my problem. As the title I am getting the above error but ONLY playing games (demanding games to be more specific). My system freezes and BSOD's (Black screen not blue) and I have to hard restart the PC. It then boots fine and will continue to work until I play a game.

Any help will be appreciated. Thank you

EDIT: updated to include more info

Things I have tried
Several different driver versions (clean installations). Only PhysX and main GPU driver installed.
Update all component drivers
Disabling SLI (this does seem to make the crashes less frequent but BSOD still happen)
GPU's in different PCIe slots
Replaced the motherboard!
use 1 stick of ram, swap out and use the other stick of ram
sfc /scannow found no issues
check the SSD for errors
Fresh install of windows 7
Malwarebytes scan found no malware/issues


Things on my list to try
Memtest
Furmark
Update mobo BIOS (although I'm sure this is up to date as mb only installed last week and drivers were taken from MSI website)
Test PSU (don't have a multi meter?). Possible swap PSU out for another.
Driver verifier (although I have manual checked in device manager for updates)
Underclock my GPU's?

I currently have reset CPU clock to stock, was at 4ghz and stable for a year+. GPU's are not overclocked but have been previously for a year+ and were always stable.
Card temps idle at 28c. Under load top out at 60c.
CPU temps idle at 35c. Tops out at 60c.

Just for further info these BSOD's stared randomly I cannot remember updated or adding any software before they started (apart from a gsync monitor about a week before). They are BLACK screens not blue with text. The sound loops and I have to hard restart my system manually. Also upon replacing my motherboard I had non of these BSOD's for 5 days before they started again. I'm sure you can imagine my disappointment...

That's all I got.... if anyone can help I will be forever thank full because short of seeking some professional help and trying the remaining things I have listed I'm at a loose end.