It's possible they're buffering less on the CPU side, I guess. On PC via driver you can select a maximum number of frames to render ahead (on the CPU side) - I think 3 used to be be the default for Nvidia. Higher numbers can smooth out choppiness and reduce dropped frames, but it can also increase input lag. Nvidia now call it "low latency mode" with the number of frames obscured, but it used to be called something more specific like "max frames to render ahead" and present actual numbers to choose. I think the driver setting for VR still exposes the actual number.
Without Jaguar cores holding them back, they might no longer need to use every single spare CPU cycle from one frame to help the next two or so to keep averages up. Perhaps they were able to shave off a frame or two of latency this way.
I used to drop the setting on PC from 3 to 1, because it made me feel 1337. Now I just have it set to "on", which I think is still just 1 extra frame of latency, but not choosing the actual number myself definitely feels less 1337.
