I'm used to the idea that the maximum resolution there was any point in trying to generate on NTSC TV sets was about 320x224 (or 240 as a compromise figure between NTSC and PAL), but according to Wikipedia the original PlayStation was designed to go up to 640x480.
But that machine only had one megabyte of video RAM. Even if you dial the color depth down to 16 bits, a single frame buffer would take 600K, and for 3D gaming you need two buffers, which would exceed the total video RAM even before trying to reserve any for textures or whatever.
Did any PS1 games use such a high resolution? If so, how did they do it?