I never understood the reasoning or desire for so much ram on a gaming card. Even at 4k resolution some games barely break the 4GB mark.
In this article, we put the GTX Titan X, R9 295X2, GTX 980, R9 290X, GTX 970, R9 290, GTX 960, and R9 285 through the Witcher 3: Wild Hunt. We do so at resolutions of 1600x900, 1920x1080, 2560x1440, and 4K to assess what hardware you need to play this recently released top-title.
www.techpowerup.com
Witcher 3 didn't even break 2GB at 4k.
Especially since the typically graphics card life is 3yrs, dumping all that cash for ram, that may not get used and tossed in 3 years seems a bit wasteful to me.
I would say 8GB-12GB for 4k for the next 3yrs should be more than adequate. I think TPU should start adding gpu vram usage to it's reviews.
Maybe graphics card makers should put so-dimm slots on the cards and make 4GB modules so people can put on 32GB if they want to burn money.
As for me I am satisfied with an 8GB card, and I don't feel like spending extra cash on ram that I will never use.