Dropping down to 16-bit should help, yes.
It might not store all of those textures in VRAM at one time, but the more memory you have in you video card the faster it will go. In fullscreen mode you've got the front and back buffers as well as texture data (1.8MB each at 800x600x32). In fullscreen mode you've also got a desktop taking up VRAM.
Having said that, it runs OK on my 32MB Radeon 9000M. Not great, but faster than 15fps in windowed mode.
It might not store all of those textures in VRAM at one time, but the more memory you have in you video card the faster it will go. In fullscreen mode you've got the front and back buffers as well as texture data (1.8MB each at 800x600x32). In fullscreen mode you've also got a desktop taking up VRAM.
Having said that, it runs OK on my 32MB Radeon 9000M. Not great, but faster than 15fps in windowed mode.