Some games i tested:
Witcher 3 @ 4K, full details
Game usually runs at 59-60 FPS, and since I use FreeSync no frame drops, nor stutter visible. Over time (few minutes) Tjunction reaches 110°C and FPS might drop to 50. Also its worth noting that at 4k Antialiasing used in this game isnt visible at all, so you can disable it.
Witcher 2 @ 4K
In most cases 60 FPS except dialogues. Game wasnt designed with 4K resolution in mind and dialogues cause FPS to drop to 10.
Near the start of the game is scene with trebuchets. When Ubersampling (Nvidia feature) is enabled, FPS drops to 27, without it its 60.
Kingdom Come: Deliverance
Cryengine. At 4k FPS in Rattay is still 47 regardless settings. Game seems to be CPU bound here. After few minutes of 4k gameplay again same problem with Tjunction. In that case fps drops a bit.
Even when i have high-res textures installed, game went only to 5.1gb VRAM usage. It was slightly a problem on FuryX.
Its an online game based on Cryengine, and to keep things smooth I play it on 1080p with frame limit on 60. GPU runs roughly on 700Mhz, not getting close to anything critical. Power consumption of whole system while playing is 140-160 watts.
So far it looks that 4k gaming, althought possible requires some tuning.
Also even when tech specs say that card throttles from 115°C, first indications of throttling are from 110°C.
I would like to keep the current cooler, but apparenlty some tuning will be required.
Alternatively DerBauer used liquid metal:
According to tests by Hexus where was obvious that chip did not had proper contact i would try the tuning with higher pressure.