I tried Carmageddon 1 when GOG first released it, but because of the poor performance I gave up playing it. Now I see that GOG updated the game installer and now include nGlide. Even if it works better than HW mode in the past I' am not happy with the 20 fps I have on my PC (2500k and 7950 Ati).

Are there any improvements that I can do so I would have at least 30+ fps?

P.S. The Win95 patch doesn't work very well for me.

The Win95 patch would be the best solution in your case or try the lowres software version.

I have an E8500 (dual core @3.16GHz) with a factory overclocked GTX260. Yes, a five year old machine. I can run GOG's Carmageddon 1 (via DOSBox with nglide) fine provided I don't use too high a screen resolution in the nglide settings. I think I can get it up to 1280x960 before it starts to give stuttering gameplay.

Windows patch should be called Intel special patch as it helps mostly people with Intel integrated cards to play at super performance when nglide sucks or is demanding (I won't back to nglide version now heh)... First to take care of is turn off vsync, disable shadows for enemy cars, cut textures at distance to far and render them to nearer, so like default settings related to shadows and rendering visible area. Other thing is 1280x720 max.