from my testing experience, using the LFB modes in duke nukem 3d and shadow warrior can come with some problems, even though i haven't heard it being mentioned a lot. the main issue that i've come across is hard to describe and capture, but it's basically split-second rogue garbled frames that show up at random times. i've had this problem occur with both geforce 2 gts and s3 vision/trio64 cards w/ S3VBE20 loaded, it's identical for those cases.

my original 4 MB matrox millennium with a 1998 bios version does not suffer from the aforementioned issue, but it definitely locks up very quickly in 800x600 as described in the help file for those games (though not sure how much that has to do with the LFB). i intend to do some testing on another millennium card with an older bios version.

i did try univbe briefly but did not like how invasive it is in terms of trying to install itself, self-selecting random refresh rates etc and it even seemed to cause some issue that made the image look washed out when i tried it on the millennium.