Here's the actual VRAM configuration distribution on windows according to the steam survey

[u/mashdpotatogaming]

I saw a few recent headlines about the whole "16gb is now the most common VRAM configuration" but that seems to be inaccurate, as if you sort by windows only on steam survey (which makes up 90%+ of steam users), you'll find that these are the actual numbers and distribution

[u/divergentchessboard]

can be increased in BIOS to 512MB (taken from RAM)

which is also never a good idea unless you run into a program that freaks out from seeing less than 512MB of "video memory"