Thing is, the quantifying fact is that nobody really has massive issues, dozens and dozens of media have tested the card with in-depth reviews like the ones here on my site. Replicating the stutters and stuff you see in some of the video's, well to date I have not been able to reproduce them unless you do crazy stuff, and I've been on this all weekend
At the best settings and WHQD we tried, Alien Isolation, Alan Wake, BioShock Infinite, Hitman, Absolution, Metro Last Light, Thief, Tomb Raider, Asassin’s Creed Black Flag ..... Let me clearly state this, the GTX 970 is not an Ultra HD card, it has never been marketed as such and we never recommended even a GTX 980 for Ultra HD gaming either. So if you start looking at that [4k] resolution and zoom in, then of course you are bound to run into performance issues, but so does the GTX 980. These cards are still too weak for such a [4k] resolution combined with proper image quality settings. Remember, Ultra HD = 4x 1080P. Let me quote myself from my GTX 970 conclusions “it is a little beast for Full HD and WHQD gaming combined with the best image quality settings”, and within that context I really think it is valid to stick to a maximum of 2560x1440 as 1080P and 1440P are is the real domain for these cards. Face it, if you planned to game at Ultra HD, you would not buy a GeForce GTX 970.
So the two titles that do pass (without any tricks) 3.5 GB are Call of Duty Advanced Warfare and of course that has been most reported to stutter is Middle Earth: Shadow of Mordor. We measured, played and fragged with COD, and there is just NOTHING to detect with the graphics memory fully loaded and in use.
Overall you will have a hard time pushing any card over 3.5 GB of graphics memory usage with any game unless you do some freaky stuff. The ones that do pass 3.5 GB mostly are poor console ports or situations where you game in Ultra HD or DSR Ultra HD rendering. In that situation I cannot guarantee that your overall experience will be trouble free, however we have a hard time detecting and replicating the stuttering issues some people have mentioned.