I've decided to get a secondary monitor for a dual monitor setup to add to my aging Sony CRT, and since CRT monitors are hard to come by, I've purchased a Samsung SyncMaster 931C (I wanted a 4:3 monitor specifically), which was popularized (and probably overhyped) by WCG 2006. However, when playing back my XviD encoded videos, I noticed horrible banding compared to how they looked like on my CRT. I tried in both, a dual monitor setup, as well as a single-display setup with all the fresh driver installs, monitor profiles etc.

I've also made sure to calibrate the new Samsung properly (I do graphics work as well, so I'm very familiar with color calibration). Whether LCD's Dynamic Contrast was enabled or disabled with everything tweaked manually, the banding was still there. One of the most apparent examples is seen on the light coronas.

I tried with both, Deblocking and Deringing enabled and disabled in XviD decoder. However, the only thing that got rid of the horrible banding was choosing "Force RGB24" or "Force RGB32" in XviD decoder options.

Can someone with technical knowledge about this please explain exactly what is happening here and why LCD playback is so much worse by default unless RGB24 and RGB32 are selected?

I've since returned the LCD for a full refund, considering it also had a couple of dead pixels on the screen anyway. But if I am to consider the same or a different LCD in the future, I'd like to know what's going on.

Thanks!