24p

All I can say for now is, that - when set to "HDMI Auto" and "1080P 24HZ On" - the Xtreamer recognizes the correct refresh rate.

On the one hand, when I play a 1080p 23.976 video, my Samsung TV will display "1920 x 1080 @ 24Hz" in the info popup, and when I play a 1080p 29.97 video, it will display "1920 x 1080 @ 60Hz". You will notice that the screen switches "off" for a second, to change refresh rates according to the video file. Auto detection does not work for all media containers though, looks like it's not working for MKVs?

On the other hand, the Xtreamer does not change the screen resolution. Let's say I play 1080p files with 29.97 or 23.976 it's no problem but when I play a 720p video, the Xtreamer does not change it's output resolution to 720p but it will upscale to 1080p, since my TV displays "1920 x 1080 @ xxHz" no matter what video - may it be 720p or 1080p.

Furthermore, accurate 24p seems to be a problem. A 24p video is resynced every 42 seconds. But this won't be noticed by most people. And my advice: don't look for it, as once you notice it you will end up looking for that frame syncing in each and every movie :)