So apparently when I was debugging the graphics system a long time ago, I figured it would be a good idea to force the graphics to always run in software processing mode. As it turns out, this completely bypasses the graphics card and runs all graphics processing on the CPU itself. I switched this one flag today and it made about a 4x speed increase in the map editor. Woo!
Karl
*P.S.: on some people's computers, only software processing works, so I left it in as a fallback