This subject was brought up in 2009, and I couldn't find any more threads on it. But I was wondering...
Could I set my TV (1920x1080) to clone my gaming monitor (2560x1920) but have it's resolution dynamically reflect the gaming monitor? Nvidia cards have DSR which runs games at higher resolutions like 4k and shrink it down to match the monitor's native resolution, resulting is (supposedly) crisper images. Does DisplayFusion have a similar option for cloning a bigger monitor resolution into a smaller resolution?
This isn't really possible to do in software. NVIDIA DSR works because the video card drivers have direct access to the hardware
We're unfortunately limited by the Windows APIs, which don't have a way to clone monitors of different resolutions. If you're not running games/videos, you can use the "Mirror Monitor" function on the Settings > Functions tab. It will clone the monitor to a new window, which you can maximize on the extended monitor. It uses polling though, so it's not good for real-time applications like video or gaming.