4k is possible at 30fps and 60fps on some titles.
GTX 970 stock
Killer Instinct runs 4k 60fps max settings. Lots of headroom for improved graphics as well.
https://c5.staticflickr.com/8/7793/27396568540_4536b2dfbd_o.jpg
GTX 970 stock
Forza Apex at slightly higher than Xbox One settings, dynamic scaling off, lots of cars on track with rain runs at 4k 60fps. I should also say reflections are way higher than on XBO as well.
https://c6.staticflickr.com/8/7302/27064636333_9427f92e51_o.jpg
GTX 970 overclocked to 1480mhz
Rise of the Tomb Raider at roughly Xbox One settings, 4k 30+fps at the location I'm at. Lowest is 31 and highest is around 37. No judder or dropping frames.
https://c1.staticflickr.com/8/7442/27063015984_fe312fabdb_o.jpg
Please note I'm not saying Assassins Creed Unity runs at 4k with highest/mostly higher settings. Best I can do is 3200x1800 locked 30fps which is still very good and with way higher settings than XBO/PS4, includes HBAO+ etc.
6tlfops is up there with a 390x/980. 390x is 5.9 tflops. My 970 trades blows with a 290/290x. Please stop with the mistake of searching for Titan X/980ti. At the moment we have to go with what AMD is currently producing and their ratings. AMD has to have a card called the Fury X which is 8.6tflops to get close to Titan X/980ti 6tflops.
What some still don't seem to get, PC benchmarks will often run with ultra everything, high AA, some of these setting can cost 15-20 frames and are simply overkill, like shadows. The cost is really high and reward is not much over high or vhigh. Some settings are 2-3 times higher spec than the what the console is running such as AO, PCSS.
Console games will have reduced LOD, AO, custom AF. ROTTR even has selected shadows turned off, no animation on plants for example. On PC you either have them all on or off for shadows. Console games have way more sacrifices going on, sometimes certain things are either missing or on low.
I haven't got time to list the hundreds of games that run at 18-30fps on console. ROTTR for example drops down a lot to 25fps in not very demanding enclosed areas, and also cuts motion blur. On PC motion blur on mine was on at all times. Point is the devs so far don't often stay above 30 anyway. You have some wiggle room if your game is averaging 30-35 frames and dropping 25 at times. Most don't seem to be bothered by this.
https://www.youtube.com/watch?v=GrUowFjsBwM ROTTR DF video
With 6tflops native 4k 30 is possible and so is 4k 60 for less demanding titles. I'm not saying this will be the norm. Many games at current console settings will run native 4k 30. Some won't. More graphics effects as time goes on will make this less likely.
Since 4k HDTVs are becoming standard when you go to buy a new one. The new Xbox will be able to deliver native 4k content. T10 for example could have some settings paired back for native 4k or give you the 1080p upscale with higher effects etc. just saying what's possible, not what's going to happen, the devs can do what they want according to Phil
There's a decent amount of 4k content you can provide like current titles, older titles plus AA and lower budget games. Games like Shadow of Mordor run at 4k with ease and some PC sites select that title to do 5k testing.
We could have devs exploiting the extra power or they could simply take the XBO version and use that power for 4k, like the games above.
Just like many months ago, I was trying to tell people on here that AMD will offer 390x980 perf at around 150w, therefore a console with this power is not fantasy, or requiring aliens to visit or going to cost $1000.