How are your temperatures?

I don't play the other games but other members have complained about Far Cry 4 after the last patch but I don't have any issues with this game. Sorry I can't be of more help ATM.

When trying different drivers are you performing a 'Clean Install' or just installing over the old drivers?
 
EDIT: What is your power supply?

Zegahertz
Yes, Uninstall all NVidia drivers and do a clean install of only garphic driver and phys x

Edit your profile and insert your system specs in your Signature so we know what we're working with like I did. You can even enter your PC on the Mods/Rigs section using your EVGA login info.
http://www.modsrigs.com/topRating.aspx
 
 

Ok I shall put my specs in sig.
As for the psu I am using a enermax revo 1500 watt I also have a corsair 1500i and powers on but don't use it as I believe it was the cause of a spark/smoke last time.

You have a very nice setup. You could have a video board starting to go on you too. Since they're water cooled it would be a PITA to take them out. You should have a DIP switch to disable each PCI-E lane for troubleshooting your video boards. Try disabling two of your boards and test each one individually using 3DMak11 or running Unigine Heaven in a loop to find the culprit.

We'll need to try isolating each video board using the DIP switch to disable each PCI-E lane making only 1 video board work at a time. You can stress by running Unigine Heaven or Valley in a loop:
https://unigine.com/products/valley/
https://unigine.com/products/heaven/
 
Both are free and both are good diagnostic tools.
 
Try running the System File Check tool from an elevated command prompt too to check for corrupted system files:
http://www.sevenforums.com/tutorials/1538-sfc-scannow-command-system-file-checker.html
 
Also, run the DX file updater: http://www.microsoft.com/en-us/download/details.aspx?id=35
Run this one too which rewrites all of your DX files instead of just updating: http://www.microsoft.com/en-us/download/details.aspx?id=8109
 

Run SFC /SCANNOW a few more times. Sometimes it just can't repair damaged files on the first pass. You can still B/U your Data files to be restored later if SFC doesn't work. It's good to make a System Image for when something like this happens. I make a complete System Image and B/U my data at least once per day but all of my drives are SSD so it doesn't take very long.

Are you using Windows 7? If so, you can try a Repair Install and keep all of your programs and files intact: http://www.sevenforums.com/tutorials/3413-repair-install.html
I have used this method more than once. You'll need your Windows installation disk.

Here's a Windows 8.1 tutorial. http://www.eightforums.com/tutorials/26095-repair-install-windows-8-a.html
It's good to have a stable operating system for troubleshooting but you could still have a video board fizzling out on you. You might try isolating each board using the DIP selector switch at some time in the future if this repair is unsuccessful.
 
EDIT: Basically when your at the Desktop insert your Windows 8.1 installlation disk. Choose 'Install Windows' and then select 'Upgrade' option but read the tutorial.

I doubt that graphic cards cause freezing... More chance memory, SSD,...
I would try definitely with Windows 7 Ultimate 7 x64 installation... That's good OS, I use him years. 
You have tutorials how to build Bootable USB Flash... after that you must follow procedure and install all updates... after restarts OS will several time to find new updates you need to install all of them, NET Framerworks all, DX web update and than start with one graphic card, if problem gone than install second and after some time third...
But you must check and Memory error with tests over night with Mem Test.
It would be good to leave memory on 2133MHz before you find what cause problems and CPU on stock... Freezing problems are worse to find culprits and sometimes is that big hardware problem as motherboard example. But definitely in most cases need lot of days before you find what is problem and for you is even harder because you have 3 cards and need to check all of them. I would start with memory, SSD, single cards, different PSU single rail absolutely to borrow from someone... What happen in idle? If no problem in idle only in games I would check with some stress test for CPU/Memory first, if that pass I would replace PSU and check games than...