Dear Karim,
thanks for raising that point...
At first I thought that the i3 "T" edition was somehow limited in the graphics output, to make people buy the i7 - but no, if I look at some mainstream i7 CoffeeLake CPU, the set of outputs is the exact same spec: the CPU can produce 4k at 24 Hz only on the HDMI output (TMDS framing), but can produce 4k at 60 Hz in the DisplayPort format. To me this is slightly funny, because the "universal digital display" outputs can do either DP or TMDS on the same port (the format is configurable in software).
https://ark.intel.com/content/www/us/en/ark/products/129944/intel-core -i3-8100t-processor-6m-cache-3-10-ghz.html
https://ark.intel.com/content/www/us/en/ark/products/191792/intel-core -i7-9700-processor-12m-cache-up-to-4-70-ghz.html
Might be a "friendly stab in the back" to the HDMI Forum :-) The DisplayPort is Intel's own standard.
Note that there are DP 1.2 -> HDMI 2.0 active adapters that can do 4k at 60 Hz.
https://www.club-3d.com/en/detail/2366/displayportt-1.2-to-hdmit-2.0-uhd-act...
You do need an active adapter, so that the PC GPU produces DP framing, as only on DP it can reach 4k at 60 Hz. A passive DP-to-HDMI adapter would be identical to the scenario where the HDMI connector is onboard, driven by the IGP "directly" (through a level shifter) - as in both cases, it is the IGP producing TMDS framing, and that's where it is limited to 24 Hz...
I've read a note that HDMI audio support might be a bit of a problem in such a setup in Linux, i.e. DP output from the Intel IGP converted to HDMI by an adapter... although I seem to recall that the report was about "problem solved".
I cannot advise you on discrete GPU's, or Nvidia vs. AMD. If you're aiming for a low-power system, the Intel IGP might be your best bet, as the lowest-power addon GPU's have a TDP of 30-40 Watt. As for CPU's, Ryzen is a very nice CPU, but low-power Ryzen is hard to find, especially if you're aiming for a passively cooled computer.
You may also want to take a look at the Gemini Lake ATOM's (Pentia and Celerons): https://www.intel.com/content/dam/www/public/us/en/documents/product-b riefs/silver-celeron-datasheet-vol-1.pdf Available on some rare Mini-ITX motherboards.
Note that their IGP can do 4k@60Hz on both DP and HDMI 2.0. And they can play back H.265 HEVC at 4k with hardware decoding in the GPU (IGP). Unfortunately I have no hands-on experience with VAAPI on this hardware. Theoretically it is supported. Allegedly it can decode source data with 10bit color depth (H.265 compressed video stream) but the DP/HDMI output is 8-bit only anyway :-) You might also want to take a look at the Apollo Lake ATOM = one generation older (I haven't checked the specs.)
Frank
Am Mi., 8. Mai 2019 um 19:01 Uhr schrieb Karim AFIFI karim.afifi@laposte.net: Hi,
I am looking for an ATX motherboard with PCI and PCIE slots, for using with new VDR 4K (PCI S2-3200+CI and PCIE Hauppauge quad), and ASTERISK (PCI Digium FXO/FXS card). At the beginning, I was thinking about an Intel 1151 socket (for best vaapi support), like this one (*): https://www.asus.com/Motherboards/TUF-H310-PLUS-GAMING/HelpDesk_Manual / Unfortunately, I noticed HDMI is v1.4, with 4k@24Hz only ! I am afraid that I need to add a PCI-E video card to achieve 4k@60Hz. Is it correct ? If so, I have two questions : 1) could you advice about fanless + VAAPI compatible product ? 2) any feedback about best plateform/chipset : AMD vs Intel ? Thanks a lot. Karim (*) using with low TDP quad core CPU, for example i3-8100T.