Ok guys, got some pretty exciting news. Tried Resolve on our MSI Titan with 1080 GTX 8GB and 6x4GHz CPUs.

Conclusions
- PLAYBACKS 8K REALTIME on a 1080p timeline. GPU memory is 5.3GB and GPU usage is abou 30%.
- Does not playback on a UHD timeline sadly. Stutters every 1 second making it useless. Good thing in Resolve is you can work in 1080p timeline but export UHD so it is not that big deal.
- I did curves adjustment and tried several different nodes like Blur, Glow, Dehaze and playback was constantly realtime. If you add many nodes this would probably change of course.

MSI and the other brands has of course newer versions with 2080 RTX cards in them so they should be about 50% faster
And also more interesting you can get laptops with Quadro 5000 RTX cards with 24GB Ram.
Andreas