It seems that the PS5 HDMI 2.1 is capped at 32gbps.
A video posted to YouTube by HDTVTest analysed the new HDMI 2.1 output from the PS5 console, and found that the maximum bandwidth it can deliver at 4K 60Hz or 4K 120Hz is currently 32Gbps. This is lower than Xbox Series X HDMI 2.1 bandwidth, which is 40Gbps.
In the video, Vincent Teoh demonstrates the capabilities of the PS5 HDMI 2.1 by using a hidden tool called Free Sync Information. This shows a tab in the corner of the screen displaying the current output specs. Teoh shows what Devil May Cry 5 looks like when running in 4K 120Hz, with the output information displayed at the same time, and it seems to be capped at a bandwidth of 32gbps. Teoh explained that this limit means that you can only get a maximum of 4:2:2 Chroma at 4K 120Hz.
The HDMI 2.1 was introduced to the latest next-gen consoles PS5 and Xbox Series X. If you're not sure what benefit that offers, the HDMI 2.1 lets the video cable transfer data at a much higher rate than the HDMI 2.0 of the Xbox One X and the HDMI 1.4 of the original PS5 and Xbox One.
To get into specifics, its maximum data transmission rate is 48.0 Gbit per second, meaning it can support a range of higher video resolutions and refresh rates, including 8K60 and 4K120, making gaming on PS5 or Xbox Series X smoother.
For more on next-gen, here’s a list of all the upcoming PS5 games.