[JiSiN]

First of all i wanna thank the whole Kodi Team & Community.
Especially "wrxtasy" for this 2 Threads (including "Hakuna99") --> START HERE - Pick the Right Kodi Box (updated Nov. 2018) & 4K HDR10 - State of Play thread - important media player limitations

Here is my Test-Result

- Test-Setup
TV:               65" LG OLED B7
ISP:              Init7 "Fiber7" 1Gbit/s symmetrical (ISP information is probably relevant for future tests)
Router:         Asus RT-AC88U
NAS:             Synology DS1812+ (Connected with Cat6 Cable to RT-AC88U)
AV-Receiver:  Onkyo TX-NR906E (only relevant for audio tests)
Speakers:      JBL SCS 178 5.1 Speaker Set (not really relevant)

- Today's Test-Device: Amazon Fire TV Stick 4K (connected via 5GHz WiFi)
Running Kodi 18 (Leia) RC1 (set to 3840x2160 10bit 60Hz - Audio set to allow passthrough for AC3 & DTS)
Video Files are streamed from DS1812+ via 5GHz WiFi (SMB-Share)

Used Video-Sample Files: Jellyfish Video Bitrate Test Files (http://jell.yfish.us)

jellyfish-20-mbps-hd-h264.mkv               20 Mbps       1920x1080    H.264    High        4.0    N/A     71 MB    Smooth
jellyfish-20-mbps-hd-hevc.mkv                20 Mbps       1920x1080    HEVC    Main        4.0    High    75 MB    Smooth
jellyfish-20-mbps-hd-hevc-10bit.mkv        20 Mbps       1920x1080    HEVC    Main10    4.0    High    75 MB    Smooth

jellyfish-40-mbps-hd-h264.mkv               40 Mbps        1920x1080    H.264    High        4.1    N/A     142 MB    Smooth
jellyfish-40-mbps-hd-hevc.mkv                40 Mbps        1920x1080    HEVC    Main        4.1    High    146 MB    Smooth
jellyfish-40-mbps-hd-hevc-10bit.mkv        40 Mbps        1920x1080    HEVC    Main10    4.1    High    146 MB    Smooth

jellyfish-55-mbps-hd-h264.mkv                  55 Mbps      1920x1080    H.264    High       4.2    N/A     208 MB    Smooth (Includes HD Audio)

jellyfish-60-mbps-hd-h264.mkv                  60 Mbps      1920x1080    H.264    High       5.0    N/A     213 MB    Smooth
jellyfish-60-mbps-hd-hevc.mkv                   60 Mbps     1920x1080    HEVC    Main        5.0    High    220 MB    Smooth
jellyfish-60-mbps-hd-hevc-10bit.mkv           60 Mbps     1920x1080    HEVC    Main10    5.0    High    218 MB    Smooth

jellyfish-90-mbps-hd-h264.mkv                   90 Mbps     1920x1080    H.264    High        5.0    N/A     322 MB    Smooth
jellyfish-90-mbps-hd-hevc.mkv                    90 Mbps     1920x1080    HEVC    Main        5.0    High    329 MB    Smooth
jellyfish-90-mbps-hd-hevc-10bit.mkv            90 Mbps     1920x1080    HEVC    Main10    5.0    High    330 MB    Smooth

jellyfish-110-mbps-hd-h264.mkv                 110 Mbps    1920x1080    H.264    High       5.0    N/A     394 MB    Smooth
jellyfish-110-mbps-hd-hevc.mkv                  110 Mbps    1920x1080    HEVC    Main       5.1    High    401 MB    Smooth

jellyfish-120-mbps-4k-uhd-h264.mkv           120 Mbps    3840x2160    H.264    High       5.1    N/A     431 MB    Smooth
jellyfish-120-mbps-4k-uhd-hevc-10bit.mkv   120 Mbps    3840x2160    HEVC    Main10    5.1    High    438 MB    Smooth

jellyfish-140-mbps-4k-uhd-h264.mkv           140 Mbps    3840x2160    H.264    High       5.1    N/A     502 MB    Smooth
jellyfish-140-mbps-4k-uhd-hevc-10bit.mkv   140 Mbps    3840x2160    HEVC    Main10    5.1    High    525 MB    Smooth (Includes HD Audio)

jellyfish-160-mbps-4k-uhd-h264.mkv           160 Mbps    3840x2160    H.264    High       5.1    N/A     573 MB    Almost Smooth (noticed a 1-2s slow down)
jellyfish-160-mbps-4k-uhd-hevc-10bit.mkv   160 Mbps    3840x2160    HEVC    Main10    5.2    High    586 MB    Almost Smooth (noticed a 1-2s slow down)

jellyfish-200-mbps-4k-uhd-h264.mkv           200 Mbps    3840x2160    H.264    High       5.1    N/A     718 MB    Not Smooth (slow downs / dropped frames)
jellyfish-200-mbps-4k-uhd-hevc-10bit.mkv   200 Mbps    3840x2160    HEVC    Main10    5.2    High    731 MB    Almost Smooth (sporadic slow downs)

The Result is ridiculously good!
I didn't expect it to run videos with over 60 Mbps Videobitrate via 5GHz Wifi smoothly.
Bought the Amazon Fire TV Stick 4K on Black Friday for 39€ just to Kodi on it.
I also bought just in case the Gigabit UGREEN Adapter that wrxtasy recommended.
But i didn't use it yet.

Well im honestly very positively surprised.

side-note: The only thing i noticed having trouble to "fix" is that in the Menu i get an audio-delay for every single movement for about 1/2 a second or up to 1 second.

Cheers!