alt Hacker NewsThe funny thing of course is that the Steam Machine has DisplayPort, and you can easily get a DisplayPort to HDMI 2.1 dongle for $20 retail. But they are targeting this being a console, and those are hooked to TVs over HDMI so it seems lame to not have a built-in HDMI port.
This is mostly an academic exercise though. HDMI 2.0 does 4K @ 60hz, and Valve have 4K @ 120hz (with 4:2:0 chroma subsampling) working over it too. Given the CPU/GPU in this machine, it won't be able to push higher than those limits anyway.
Replies
Only if the adapter is active; passive ones just tell the GPU to switch protocols to HDMI or whatever, so those are still kneecapped by driver limitations.
Edit: I just checked Amazon and active adapters are a lot cheaper (and less niche) than they used to be, though there are still some annoying results like a passive adapter which has an LED to indicate the connection is "active" being the first result for "DP to HDMI 2.1 active".
For some reason that DisplayPort is only 1.4. That's only ~26 Gigabit/s. While HDMI 2.1 is ~48 Gigabit/s.
You can make up some difference with DSC, but I think that requires the display to support it: dongles won't decode it.
I'm guessing the DisplayPort is there to support the original Valve Index directly.
I have my high end PC connected to a TV so it ruins my chances of ever switching to Linux. But yes for the Steam box this doesn't matter.
The more pertinent issue is that many TVs will only do VRR over HDMI 2.1, and many active DP to HDMI 2.1 adapters won't pass VRR through either.
That's also why the Switch 2 supports VRR on its internal display but not when connected to a TV - the dock can't encode a HDMI 2.1 signal. That's just Nintendo being Nintendo though, they could support it if they wanted to.