alt Hacker NewsI'm going to guess if you did it on the video card and simply disabled those enhancements it would be considerably more energy efficient than doing it on the CPU as well which (a) means your laptop battery lasts longer on a charge, and (b) also opens up the possibility of not needing a particularly powerful CPU in order to juice the resolution, because the video hardware is doing the work for you.
From a programming perspective I do completely get the desire to have the CPU do all the work though - if you want absolutely everything under your control it's easier, and especially if your game is single-threaded.
I've mentioned this elsewhere, but nowadays, anything you see out of an HDMI/DP/eDP cable comes out of a GPU. Modern OSs make it impossible to do 'software rendering' any more; it's just that much faster and that much more efficient, even if it is harder to program directly. Even IPMI BMCs have a tiny GPU doing stuff.