But that's not what's happening with Intel, they clearly have on their spec that the cards run natively with HDMI 2.0 and can support 2.1 through protocol conversion. I don't know what bandwith or feature limitation will look like, but they didn't hide that their solution is not "native" or as native as usual I guess (I mean I don't know how it's usually done anyway, I think the protocol display driver is not part of the gpu die or we wouldn't have gpus with different number of dp/hdmi ports namely on workstation cards but whatever).
I know there was this video where Intel's rep finally clarified the situation surrounding HDMI. But this was after questions were explicitly asked. They would not tell us on their own. You haved to beg them to publish and challenge them to provide basic connectivity information.
On Intel's official website, the situation is still confusing and they should be called out for this by tech community. Here is the screen shot of the official spec.
As you can see, both HDMI 2.0b and HDMI 2.1 have a star "*" attached to it, but at the bottom of the page this star small print is nowhere to be found. Intel, WTF?! DP has two stars "**" and there is a clear explanation. This is what always makes me suspicious that something is being hidden from the public.
They should simply say the following, for the sake of simplicity and transparency:
*HDMI 2.0b TMDS 18 Gbps - A380 and A580 cards
*HDMI 2.1 FRL 40/48 Gbps - installed on founders A750 and A770 Limited Edition only; AIBs have an option to add FRL support via PCON
There are two ways to get FRL signal on GPU:
1. install native HDMI 2.1 chip on PCB (Nvidia and AMD GPUs)
2. install PCON chip on PCB that is fed by DP1.4 signal and then converted into HDMI FRL protocol (A750 and A770)