HDMI 1.4 only supports 4k resolution in full RGB mode at 30 Hz, and does not support HDR. HDMI 2.0 supports 4k resolution in full RGB mode at 60 Hz, and supports HDR. The PS4 Pro supports 4k@60Hz through HDMI 1.4, but only in YUV420 mode, which has reduced color information.
The original PSVR processing unit, which sits between the PS4 and the display, has only HDMI 1.4 support, which is a problem with the PS4 Pro and a 4k display. This means that the PS4 Pro will only be able to use YUV420 (rather than RGB), and will not support HDR.
Once you understand these differences, the distinction is quite clear: HDMI 2.0 is good for 4k and HDR, HDMI 1.4 is insufficient. If you have a 4k display, and a machine capable of outputting in 4k, prefer HDMI 2.0 whenever possible, and avoid HDMI 1.4 whenever possible, on all sides.
Yet, for some reason, manufacturers seem quite keen on hiding the HDMI version from their advertising material and sometimes even detailed technical specs. Oftentimes you can't find this information anywhere. Be it 4k displays, HDMI splitters, HDMI switchers, or other such devices dealing with HDMI, sometimes you just can't find which version of HDMI they support. Yes, sometimes even for 4k displays (I have encountered several examples.)
Some months ago Sony released a new version of the PSVR, for some reason without much fanfare. It was such a quiet launch that I just became aware of it myself, even though it happened many months ago.
One significant improvement in this PSVR version 2 is "HDR passthrough".
That's it, "HDR passthrough". Does this mean that the new PSVR processing unit box has HDMI 2.0? I have no idea! I can't find this info anywhere! I have searched and searched, and I can't find anything.
Even the official technical specs are not useful in finding out. The specs say:
No mention whatsoever about which HDMI version the processing unit box supports. Does "HDR" mean it's HDMI 2.0? Who knows.
- VR headset: AUX port, HDMI output port, HDMI TV port, HDMI PS4 port, USB port
- Processor unit: HDMI port, AUX port, Stereo headphone jack
Processor Unit Function 3D audio processing, Social Screen (mirroring mode, separate mode),
Cinematic mode, 4K and HDR (pass-through mode only)
I found one discussion thread at the official PlayStation forums where a person asks specifically if the new PSVR processing unit supports HDMI 2.0. From the three answers none of them confirmed this. None of them actually answers that question specifically. They just repeat what the technical specs are saying.
I literally cannot find this information anywhere on the internet. It doesn't seem to exist.