VRAM Is a Layout, Not a Texture Folder
The original PlayStation has 1 MB of VRAM, but treating that number as a simple texture budget is misleading. VRAM is a 1024 x 512 field of 16-bit words shared by display buffers, texture data, and color lookup tables.
Every rendering decision changes that layout. Resolution, color depth, double buffering, texture format, and palette placement all consume the same address space.