4K+1080 is a matter of downsampling, not re-rendering. You could even do the downsampling “for free” if it’s done by the part of hardware that reads from the fr

4K+1080 is a matter of downsampling, not re-rendering. You could even do the downsampling “for free” if it’s done by the part of hardware that reads from the framebuffer to generate the output signal just by skipping lines. Stereoscopic rendering (e.g. 2x4K) can far more expensive than 8K rendering despite brung half the pixels because all of the non-pixel-related scene rendering calculations have to be re-done to account for the two different camera positions.