Carmack's talks continue to be the best possible use of 90 (or 120, or 180) minutes for me. His crisp, honest, well-grounded and well-articulated discussion around real-world work to push the technology envelope makes him worth listening to any time I get the chance.
It's super interesting to hear him discuss how computationally demanding VR is. The Oculus Quest was announced, which is a standalone 6DOF headset which is computationally roughly equivalent to previous gen consoles like PS3 and XBox 360. But, as he points out, those were rendering at 30 FPS at 1280x720, often with no MSAA. To support VR, the system needs to render more pixels faster: 1280x1280 times 2 (one image for each eye) at 72Hz. This means roughly 8x the number of pixels being pushed, with an additional tax to add on 4xMSAA.