The tech session with Mark Cerny was signposted as far back as the PlayStation Meeting at the beginning of September, and it didn't fail to deliver a treasure trove of new information on the hardware make-up of the new machine and the ethos behind it. The highlights are as follows.
Additional 1GB of DDR3 RAM - used to swap out non-games apps (eg Netflix) from the 8GB of GDDR5
512MB available to developers for 4K render targets and framebuffers
Another 512MB utilised for handling a 4K version of the dynamic menu front-end
New ID buffer for tracking triangles and objects, opening the door to advanced spatial and temporal anti-aliasing
4K framebuffers either created from simpler geometry-only rendering or more advanced checkerboarding
Some developers - eg the developers of Spider-Man and For Honor - producing their own 4K techniques based on four million pixel framebuffers
Double the compute units, laid out like a mirror of the original PS4's GPU. Half the CUs deactivate when running in base PS4 mode
2.13GHz CPU and 911MHz GPU in Pro mode, running at 1.6GHz and 800MHz respectively in base PS4 mode in order to lock back-compat with the standard model
AMD Polaris energy efficiency improvements enabling more power in a console form factor
Delta colour compression technology arrives in PS4 Pro, maximising memory bandwidth. Not seen in PS4
Primitive discard accelerator culls triangles from the scene that aren't visible
Enhanced 16-bit half-float support
Improvements for running multiple wavefronts on the compute units - more work per CU
New features from AMD roadmap - the ability to run two FP16 operations concurrently instead of one FP32, plus the integration of a work scheduler for increased efficiency
Advanced multi-resolution support for increased performance in VR titles