Originally Posted by Manni01
You shouldn't have any problem getting UHD/4K from an AMD HD7xxx to the X500. I have an AMD HD7870 in Win 8.1 Pro (catalyst 14.12) and it feeds the X500 fine in UHD (up to 30p) or 4K (24p only).
First try to connect the JVC to the HTPC directly, using just one fast HDMI cable (certified for at least 10.2Gb/s, i.e. HDMI 1.3/1.4 bandwidth). You need to rule out everything in between first. Also install the latest catalyst drivers (at least 14.12). If the issue disappears, then you know there is something wrong in one or more of the cables/devices between the HTPC and the PJ.
If you still have issues with a direct connection, check the pixel format in the catalyst driver and try various options in YCB or RGB to see if the problem goes away, as well as the HDMI setting in the PJ (I suggest HDMI standard). Then set the dynamic range accordingly to get the correct levels depending on the content played (Desktop or video content) and the pixel format/hdmi standard used.
Also make sure that you select a refresh rate of 30p max, and select UHD (3840x2160) rather than 4K (4096x2160) resolution in Windows. The JVCs can't support more than 30p in UHD/4K due to the HDMI 1.4 bandwidth limitation.
On this note, it is definitely worth checking out some of the 4k/uhd clips available for download. When I got my 4910 a year ago, there were only a few. Tears of steel was/is still a good one.
Now you can find demo clips from LG, Sony, etc. that are gorgeous! Look for ones that are in the 1-3gb size range for a few minutes of video. Some of the smaller files are more compressed and while they look fine on a smaller screen, the higher bitrate matters at this size. Some are in 30fps and other are 24....so if your graphics card can't switch on the fly (like my macbook pro), be sure to set it to match the clip or the motion will be choppy. Find downloads, not streams. This is good site for samples: http://demo-uhd3d.com/categorie.php?cat=demouhd
While not true 4K, it does seem as others have pointed out to be about 1/2 way there. If you get right up to the screen and look at some of the better 4k samples, the level of detail is more than you'd see from good 1080p sources, yet not as fully resolved as a native 4k display. Granted these clips would look excellent in 1080p, but I do think you get close to 1/2 of 4k. One clip that has closeups of iguanas and a multicolored chameleon reveal very fine detail even up at the screen. Pretty impressive.
It was enough to convince me that if UHD BD players offer dual HDMI outs and an HDFURY type box can get around the HDCP issues, there is enough to be gained to seriously consider purchasing. Of course that depends on player prices and content availability. I'd rather put my money into buying UHD discs anyway...but I hope they come as combo packs with a BD copy as well.