The PlayStation 5 has an HDMI 2.1 port that supports Variable Refresh Rate (VRR), but this is not enabled at launch and Sony has confirmed this will only come through a future system software update in its updated PS5 FAQ.
This is unusual and the VRR ought to work by default the same way it is supported in the Xbox Series X, Series S and the One X. This is not surprising since the PlayStation 5’s storage expansion slot is also not enabled by default; Sony has also confirmed that will only be possible via a future system software update.
The PS5 is capable of 120fps at 1080 and 4k. It is not uncommon for some games to suffer occasional dip in framerate, and with VRR enabled, this can make for a smooth gaming experience.
When Sony eventually releases the update, gamers would still need a TV that supports HDMI 2.1 to enjoy this feature.