vodeo card memory all started with the 3dxf voodoo 1 ...
(add on 3d vid card)
befor that video card maker tryed to make an api that worked with hardwere to give games more speed but didn't relly workout till 3dfx poped on the sean
dosbox is made for older softwere (dos) not emulated 3d hardwere api in dos
2 megs of video memory gives you 1024x768 res at 32 bit colors max .in dos its more then you need
dos games just send data to the vid card over the pci\isa\eisa\vLbus...thay dont use vid card memory .thay just stream data dma stile to the card
8 megs for the vid card is like voodoo 2 land
4 megs frame buffer 8 megs texture momory 12 megs totle 😒
btw back in the day overclocking you isa\pci\VLbus was the best way to get more fps in video games ^^ as long as the rest of the computer diden't bug out when doing that
3d api worth noteing
glide
mini gl
direct3d
directdraw
opengl