It looks like the feature is mostly a success.
Some lucky users are currently testing PlayStation 4 Firmware 5.50, KEIJI and one of the many new features of the firmware is system level supersampling. Finally offering the feature natively similarily to what the Xbox One X does, supersampling is a setting that PlayStation 4 Pro users who are still using a 1080P screen can use to render a better image quality for their games. Basically, supersampling tricks the console into rendering out a 4K image and then the system scales that back down to 1080P resulting into a crisp image quality.
At least that’s the claim from Sony, but it seems like the tech masters over at Digital Foundry have done the homework to say that the setting works amazingly well. When active, “The improvement to image quality is clear” says Digital Foundry. Jaggies disappear, more detail is displayed and the image, down to the the sub-pixel is improved.
It wasn’t all rainbows and sunshine however, some titles they tested like The Last Guardian, which is known to have performance issues with the 4K mode, don’t play as nicely with the mode since the system is essentially locked into the 4K mode.