Hi,
Assuming all of your CGX / W3D settings are correct (make sure bitmap cacheing is enabled for CGX, warp3D needs it), check the following...
The problems youre having could probably be down not to how much memory you have overall, but how much ram you have on the gfx card.
IIRC, the CV3D has only 4Mb. For hardware accelerated rendering, everything the 3D chip needs to use must be present in the cards memory.
That means your display, back buffer (for double buffering), z-buffer and textures all need to fit into the 4M.
Assume you have a double-buffered 640x480 display, 16-bits deep and a 16-bit z-buffer, that equates to (640x480x2) x 3, which is 1800K.
Thats half of your 4M gone already.
Warp3D itself manages the texture cacheing, making sure that whatever is not needed at the moment is swapped out of video ram into normal memory.
One thing I recall is that there is a setting for the card that reserves 1M of the memory for 'multimedia' stuff - an overlay I think. I'm not sure if you need to disable this (to free up more ram for textures).
When running warp3D apps on your CV3D, try to free up as much video ram as possible. Close any unneeded screens and windows. Then drop your workbench to 640x200x8 bit (fewer than 256 colours wont matter on a chunky display) and lose any patterns etc. You could save a settings preset for this so you can just simply load the prefs again later when you need to.
This all may sound drastic but it will free as much of your VRAM as possible.
Finally, if the 3D apps you wish to run allow it, use lower texture detail settings and turn off mip mapping (each level of mip map uses more video memory).
Hope this helps...