Just posted at my site:http://greybeard.xoom.it/virgiliowizard/settings
It gave me some improvement in framerate on my system (AMD Athlon 64 2GB RAM - Nvidia 9400 GT 1GB).
Sun glare still gives some stuttering, but you may turn it off in RB preferences (I left it on because I can't live without it, lol).
Of course, you need Glide2x.dll fron OpenGlide Wrapper 0.08. If you do not have it yet: you may find it at von Oben's site, RB3D Misc Files:http://vonoben.free.fr/
In respect to INI included in this one, I increased only Texture Memory to 256 MB, Wrapper Priority to 2 and reduced Monitor Frquency to 60 Hz, since on my LCD can't notice any flickering at so low value, while higher ones (like 75) should for sure require some more resource.