My CAC-1170 has arrived and I have set it up with my Sony 43x8000D screen. The TV has a setting that enables HDMI2 and 3 inputs to do hi-res 4k, so I have turned that on and plugged into HDMI2.
So far I can only get 3840×2160 @ 30Hz.
My confusion about the capabilities of my NUC/processor have mostly been sorted out. The processor family in general supports 3840×2160 @ 60Hz as the CPU has a 540MHz CDCLK (pixel clock). That res/refresh needs about 500MHz so all good. However, my NUC has the i3 4010U – the U is for ULT which are the lower power versions. These have a CDCLK of 450MHz which is not high enough to support 60Hz. It should be able to do 50Hz though (see below).
The NUC should be able to do 3840×2160 @ 60Hz using MST (multi-streaming displayport). I’m assuming that MST for a single hi-res monitor was a stop-gap technology whose time has passed and that the CAC-1170 will not convert DisplayPort MST to HDMI2.0 (a quick search did not turn up any relevant hits, although that is hampered by @MST1407’s username 🙂 )
So, for now my goal is to get 3840×2160 @ 50Hz. I do not yet have this working. I do have 3840×2160 @ 30Hz, and to be honest I have no problem using this. I don’t game – I just use xterms and chrome for the most part. I played a couple of videos and they were fine (but I’m not sure I have any videos > 30Hz). Perhaps if I had a desktop that utilised a lot of animation, I’d notice the low refresh rate, but I don’t.
I will keep trying to get 50Hz going. I have tried a few modelines at 35Hz, 40Hz, 45Hz and 50Hz and none of them work. I don’t know why yet as the pixel clock for the modes is within the machine’s CDCLK.
The other issue I have is that DPMS does not work. When the screen saver activates the TV says there is no signal on the screen and does not blank the display. I’m not sure if this is due to the CAC-1170 or the TV. I will experiment with the HDMI port on my NUC to see if the screen will blank. Even if I can’t get DPMS working, my backup plan is to use the HTTP POST protocol that the TV has for control purposes to send the screen into standby using that instead of DPMS.