I sold a MSI 970 to get a KFA 980 first with the 4k monitor and it was okay but I had to turn down detail and it ran hot. I was quite surprised how hot it got. It also didnt seem smooth. So then when the Galax were on offer I went for two. First time running SLI and I was surprised about how trouble free it was. The settings I had to turn down for the 980 I could whack on full/ultra. Only thing that made it chug was AA but even with on/off you cant see a difference.
I played the latest COD all way through the end with everything on max and also tried Shadow of Morder Ultra textures which was smooth I was surprised. If I turned gsync off though I got stutters. Turned it back on and smooth again.
The Galax did run hot though. 60c-65c bottom 70-80c top. When I found out I could not install full cover waterblocks I then installed two Kraken G10's with AIO coolers and now the top maxes out at about 51-54c and the bottom 40/41c. Thats with the fans on really low too 650rpm.
Then I sent my monitor back, sniff, and not seen it since.....