It was a strange one, but restarted my system and used the DP cable supplied with the monitor, now all seems fine. May be my old cable?
Anyways, now I have had a good play around, have to say really impressed. The colours are great. I was expecting less after reading how TN panel apparently are, but not in the least disappointing. Probably notice a difference with an IPS sat next to it. Viewing angles not bad at all.
144hz with G-sync is ace, definitely allowing me to crank up the graphics a bit as the stuttering is not apparent when its in to 50-60 fps range as it was before.
BF1 is something else now! It was my experience with BF1 that started me looking to G-Sync as I had a very apparent lag, first game I really noticed it. Maybe the placebo effect, but certain I am doing better now. Playing classes that I avoided such as sniper and medic as I can actually hit moving targets now, instead of my old 'spray and pray' tactic!
Highly recommended, looking forward to experiencing a lot of my titles again with this display.