Math done 12MB should be the amount required.

Paractically, 32 bit per pixel color information and 2048 x 1536 pixels so 2048 x 1536 x 32 = 100,663,296 bits. Divide by 8, then you have 12,582,912 bytes. Convert it to megabytes (divide by 1024 x 1024) and you will get 12MB. So, theoretically, anything with 16MB VRAM will do.

16MB for 9x/XP. Significantly more for Win7/8/10.

That's framebuffer memory.

Some cards (voodoo?) with 16 MB can have their memory divided between framebuffer and textures memory, and not be able to get that resolutions.

Also, keep in mind that RAMDAC may limit available resolutions.

I think by the GF3 era most gfx cards were supporting 2048x1536. So it must be way under 64mb even. Ive use my GF4 4400 Ti in 1920x1080 actually it surprised me in how good it worked. On the desktop only of course.

I'm reasonably certain I had a G400 MAX run at that resolution, and that's only 32MB.

However, there are very few monitors that properly support it. I have two IBM CRT C220p monitors that top out at 2048x1536x75Hz, and it'll happily sync up to that, but there's insufficient phosphor to fully resolve any standard 4:3 image above 1600x1200. It still looks good, but some pixels are being lost.

There are a few TFTs that support that resolution, but they're rare..

The Riva TNT should even be able to pull that off

Here's an old 1998 q3 screenshot at 2048x1152

I know my Quadro 2 MXR with 32mb of ram will do 1920x1200 at the desktop. Not sure if it can do it in a game 🤣

you should have some margin there, depending on the cards technology and settings; still iirc tnt was the first card to run quake 2 in 1600x1200 semi fluid, and tnt2 with 32mb was the first to run that res on quake 3 i believe (run, not just show a picture);