Fantastic responses, thanks ever so much. I've isolated the problem :D
Running the cards individually, see results from card 1 and card 2
Now I'll strip the waterblock from card 2 and reapply thermal compound, hopefully its just that or something similar and not the card itself
although it's...
I've had my rig for about a year now and something is getting really hot and for the life of me I cannot work out what.
When playing CPU intensive games like ARMA 3 I start to get artefacting after about 5 minutes, which leads me to believe its heat related, it gets worse the longer it's...