Yeah my bad, typo -- i'm on 3.60.09. Honestly, i don't find HDR Game to be dim at all. HDR Cinema User is the mode that D-nice used when calibrating HDR. Only HDR Game on this firmware has the same type of HDR mapping curve as Cinema User (whether to clip content beyond what nit the display can handle, or preserve more detail). I will note that Cinema User is definitely 10% brighter than Game for some reason.
I had a chance to play around with the PS4 (non-pro) and some HDR games yesterday. There is definitely a huge difference in brightness between the HDR Game and Cinema modes on my set. I don't mean the highlights, they can both get about equally bright there, but the midtones in Cinema are way brighter. Otherwise they do look identical in terms of color reproduction.
What I discovered is this difference in midtone brightness is entirely due to the dynamic contrast setting. With DC off in both HDR Game and Cinema they do indeed look the exact same. When I set it to low in both modes, however, the difference is drastic.
In HDR Game mode DC seems to simply increase contrast by increasing midtones and decreasing shadow detail. This is very apparent in a dark areas of games, where shadow detail appears to get crushed. DC on low in Cinema mode works entirely different, and it does appear to boost the midtones but without sacrificing detail. I imagine this is what LG means with the Active HDR feature (DC on low = active HDR).
The DC HDR processing for Game mode and Cinema modes is very different, and not worth it for Game mode so much. DC on low for Game mode results in a relatively small midtone brightness increase. Raising it to high actually matches Cinema's midtone brightness, but reduces shadow detail significantly. I'd say DC is best left off on Game mode, and on for Cinema.
I did come to the conclusion that HDR game is actually very usable and pleasant looking as long as you're not in a bright room. The highlights still get as bright as other modes, but the overall picture is simply less bright.
Can you please confirm you have Dynamic Contrast set to low in Cinema mode as well when comparing with Game mode? This is the recommended setting per LG and calibrators since it enables Active HDR (generates dynamic metadata from static metadata). Again, it definitely doesn't appear to function the same way in Game mode.
Yea '17, but FW 3.60.16. Note I am talking NON-PC mode. If you match the available settings like for like the only difference I can eye ball is colors in Game are slightly more saturated by comparison at the same value, but the modes are seriously close.
*Strike Edit* I actually had Game Color 5 points higher, like for like they actually appear to be identical.
Would you also please confirm Dynamic Contrast is set to low for both Cinema and Game modes when comparing?