Yeah, unfortunately they will be slowet. Probably little more than 1/2 "normal" speed. Sucks a bit I guess considering a lot of the better games will be 3d.
I think genetic species needs the updates to work in non pal/ntsc modes too by the way.
Soliton is a pretty darn good version of solitare if you get desperate 
For most of them so far, its been okay actually. Gloom was the only one that was noticeably worse. Nemac IV runs like a charm, but maybe that one just plays nice.
THanks for the suggestions btw people
edit: Tried the update and I can't get Genetic Species to work in VGA mode. Any suggestions? No graphics card here.
Trapped works for the main menu, but doesn't work when you get into the game itself