I've been debating for a while on either upgrading to a 4GB VRAM GeForce GTX 960 (often around $220-260) or 4 GB 3.5 VRAM 970 (often around $300-400).
Obviously, 2 GB VRAM GF 960 was never on the table for me. Always was aiming for 3GB VRAM or more, preferably 4GB or above.
I really don't like that the bus on the GTX 960 is 128-bit, while on the 970 it's 256. Plus, my 560 Ti has a 256-bit bus.
Still, that 4GB VRAM on that 960 flavor buffer is quite big. Well, certainly bigger than my 1 GB VRAM GF 560 Ti.
There's other cards with more VRAM - i.e. Radeon R9 390x has 8GB VRAM; a new GF 980 Ti flavor has 6 GB VRAM; and we won't get into expensive $1000 NVidia Titan card land (12 GB).
Even though performance for bang-for-buck, the 970 is probably the better buy for future-proofing - i.e. just check the benchmarks online...the 970's gonna handle 1080p + 1440p way better than the 4GB 960. It might do alright w/ some games at 4K. But, not having that extra .5 GB VRAM always open - that could be a problem for some games at some higher settings...especially even more so at 4K.
4GB 960 seems really geared for those doing w/ 1080p...and sticking with that. I don't have 1440p monitor yet, I'm still on 1080p here. I could be wrong here - but I don't really see myself moving to 4K anytime soon, honestly.
My 970 concern was always the 3.5 GB issue, as it might not be enough of a buffer for the higher-texture quality, if I want the option to run it and think I might be able to handle it w/ certain games. Some games want 4GB VRAM (or more) for their top settings. Go see Shadow of Mordor, The Evil Within, Ryse, ACU, FC4, The Crew, etc. While the 4GB 960 might not run it as well period (i.e. 4GB 960 is about half of a 970, spec-wise + performance-wise on everything except the 4GB VRAM buffer), at least there won't be stutters when trying those textures, if it needs to eat over 3.5 GB...since the other 0.5GB is often swapping what it's doing (could be used for other things, could be used when necessary if it calls for the 0.5 GB but it's still on a way slower bus and can take forever to find it, or whatever).
At least if 4GB 960 runs like shit on higher settings on a game, it runs like shit straight-up consistently. 4GB 960 won't be have the 970's sudden stutters, slow-downs and weird things just b/c it can't find that last 0.5 GB b/c that channel's slow (32-bit bus) is delegated to doing....well, whatever it feels like doing!
AMD was never an option I was looking much at + considering. While the 3 GB VRAM Radeon R9 280's 384-bit bus slaughters the 4GB GF GTX 960 128-bit and it outperforms that card quite a bit - the 3GB VRAM buffer's still a wall to me. BTW - the R9 280x is very similar in pricing to the 4GB GeForce GTX 960, that's why I'm comparing them.
I'm a NVidia guy, for better and/or for worse. I've been using only GeForce cards since the old 64 MB GF2 MX 400.
