This might be an odd question, but I was wondering if you could improve GPU performance with games, comparatively, when using doubles/halves of the native resolution, instead of an odd ratio of that.
Lets compare the situation with a metaphor first. If I'd give you a standard A4 sheet of paper, I bet you can more easily fold it in half than 1/3rd. Same goes when I'd give you two sheets of A4 and ask you to create a A3-size rectangle, instead of a not-A3-but-larger-than-A4-shape.
To go back to the actual situation: My Macbook has a native resolution of 2880x1800. But the game offers a variety of resolutions, such as 1440x900, 1680x1050, 2048x1280, 2560x1600 and for some reason also 3360x2100, which is above the native resolution..
If we'd include the sheet of paper thought in resolution scaling with games, compared to the native resolution, I'd say 1440x900 could run even better than 1280x800, because the GPU could simply say: reduce all pixels by 50%. Not only is that an easier calculation, but it's also much easier to interpolate, if that's the correct word for it to calculate how the pixel should look like.
Sudden thought: This does assume the game environment is rendered at the native resolution and thereafter downscaled to the set resolution, which is probably wrong. That said, I do think it'd be easier to render at half the resolution than something like 40%.
This idea does apply to Photoshop with increasing and decreasing the resolution: Always increase with halves and doubles. So why not games?
I'm not only very interested in the actual answer, but perhaps makes it easier to set a resolution for a battery vs performance question :)