HDR Update *Mass Effect*
Finally, I could enable HDR in Mass Effect. But the results are pretty bad. Almost the same as I just would activate HDR within windows and play just some game. I strongly assume that this is an issue within the software, but I cannot confirm for sure. It also can be that games, especially mass effect (but this would be strange) just look bad with HDR, especially with this "low" brightness.

Update 2: Mass Effect and HDR
I've read some articles that Mass Effect Andromeda in HDR looks (sometimes) washed out. Especially the menu will lose color intensity. So some places look better and some worse compared to non-hdr game content. Based on this video https://www.youtube.com/watch?v=cgBzpYT ... u.be&t=103
and this Review
https://www.gamecrate.com/samsung-chg70 ... view/16348
they say depending on the Image content sometimes it looks worse, sometimes it looks better. You have to consider, HDR currently with current game content looks so bad to me on the CHG 70 that I thought there is 0% HDR support. Especially in games, it's probably pretty hard to benefit from HDR while within movies mostly profit from HDR. And even in movies, it's mostly not like another world and sometimes is the difference pretty slightly. So I think it also depends strongly on how good a game is programmed or how good a movie is recorded. While the movie "Life of Pi" looks awesome on an HDR 4k TV and "The Revenant" pretty decent into my eyes.

I talked about bad black levels within HDR, but I think this is just because it looks like you have a contrast around 400:1 or something. Even standard mode on contrast set to 0 looks better.

Video: https://limscave.de/media/samsung_chg70 ... Effect.mp4
Flickering
At HDR you can see the monitor does not flicker, this is because the brightness settings within the OSD are set to 100. Everything "under" around 200 cd/m2 starts to flicker

Samsung CHG70 HDR Update Conclusion Overview
HDR has currently Problems on PC which will be fixed for sure
Even with these fixes I would not recommend the CHG70 for HDR content
and especially not for HDR Movies on a 4k Blu-Ray Player
1. Too dark (not enough brightness, check the link in the video description for current
Samsung brightness issues within displays.
2. Not enough dimming zones. Of course, direct LEDs or dimming zones are not needed
necessarily, but they can improve the overall image quality drastically, especially within HDR

HDR on the PS4 looks amazing
1. Sometimes a bit worse sometimes better on the CHG70
2. Within the game "Horizon" it looks awesome and I already can imagine how good
this will look on an appropriate display
3. Nevertheless, WQHD on PS4 is not optimum. If you play on 4k the PS4 downscales to 2k - you still will have a sharp image but with the disadvantage of lower framerates while the game still is rendered in 4k. On Full HD the Monitor has to downscale and a native Full HD monitor will be sharper than a WQHD Monitor. So in the end, with WQHD on a console you can't profit within 4k and loses sharpness within Full HD, you should keep this in mind.