Checkerboard Rendering renders half of the pixels nativly.
Well. Sortof. There are still aspects of the render that do process at native resolution, so it's not a direct halving of cost. Depth/Stencil, object ID, and pre-pass alpha testing shader evaluation (optional) are native resolution to aid the CB reconstruction - and obviously the CB resolve / upscale itself also occurs at native res (plus and subsequent passes).
It depends on the implementation though. There are ways (and game examples) that render with properly halved processing all the way to the final upscale, with obvious reduced resolve quality.