What's the resolution on games with widescreen support games with no hd support?

I was looking through a list of Original Xbox games with alternate display modes on Wikipedia:

https://en.m.wikipedia.org/wiki/List_of_Xbox_games_with_alternate_display_modes

I noticed a lot that say they support widescreen but not 720p. I looked around the web and couldn't come up with much info. I'm wondering if anyone knows how it accomplishes this and what the resolution is? Is it 480x640 or 480x720? Has anyone tried this and how do they look? Are they all stretched out? Is it better to just leave any game without 720p in 4:3?

Submitted by buttman88 | #Specialdealer Special Offer Online Shopping Store 2016