That should be enough RAM, but it depends on what else is running while you play. Also what OS you have?
Windows XP.
If you could provide a screenshot of what you see it would be easier to help you.
Hrm. I wish I could get you a screenshot from the Tunnel, but I recently went on to the Castle Center, and I can't find a save file anywhere. Basically, what's going on is that the only high-res texture that is applied is that of the floor, while all other textures in the tunnel are the standard game textures. This is similar to the "parchment" of the pause screen, in that only the right half is high-res texture.
Is it the textures that aren't loading, or is it the polygons themselves? Do you get blank spaces entirely where a texture should be?
No blank spaces, just the existance of original textures in a few areas, mostly in the tunnel (it's fine pretty much everywhere else, pause menu aside), instead of the high-res textures that are supposed to replace them.
You might try going into the RICE video options and checking off "Near Z-plane Hack" in the the "current game options" while the game is running. If "Use Software vertex clipper" is on in the DirectX tab, try turning that off. Try turning on "use software and lighting transformation" (DirectX tab)
I'm actually using OpenGL here, since I don't have to deal with the absent sound channels resulting from using Direct X. Also, I experimented around with these options when I still used DirectX, and had no luck.
Also, I should add that these problems remain the same even when I'm using Glide64 (Naplam release) for my video plugin. Glide64 seems to negate terrible the slowdown that I experience in a few sections, such as the Art Tower in particular. However, for some weird reason, only a single frame of the custom fire animation remains intact. This doesn't occur with Rice.