Texture size adds up in memory, but they are only loaded when rendering. P8/P9 implemented a texture cache which decreases the need for memory. But with sparse memory it still uses a lot of it. A V4 has separate texture maps for body, head, limbs, inner mouth, eyes,eye lashes and possibly tears and their bump maps and in some case specular maps. In V4 a lot of them are often 4096x4096. Each taking up 32MB (If I recall correctly) - so that adds up pretty quickly.

There are a number of scripts which can remove the unused morphs. You can also let Scenefixer create a FBM inject file and then use that one on an empty V4 figure. Add the expression morphs again and you have a version which is a lot smaller