http://www.sweclockers.com/artikel/17278-snabbtitt-asus-pq321-med-4k-upplosning
I can't understand it, but I can make out what the graphs mean. (They're pretty universal anyways.)
So, hope this helps. I think it shows that maximum settings won't work for all games at 4K, and maybe the importance of Anti-Aliasing will decrease. But also, with the upcoming HD 9000-series GPUs in October (according to rumors from Videocardz.com, WCCFTech and X-Bits Labs), this might be a huge deal.
Think of the difference between GTX 580 and HD 7970 at launch. That's going to be similar, since it's both a die-shrink and new architecture. (GTX 580 was 40nm and HD 7970 was 28nm - architecture was of GTX 580 was Fermi, while GTX 600-series is Kepler).
We might have to wait until Q1 2014 until we see Maxwell GeForce cards coming out, in the GTX 800-series, so anybody with brand new GTX 700-series GPUs might be slightly disappointed in a few months.
For those curious about the articles I mentioned prior [note: these are rumors and speculation, albeit with some limited credibility and photographic evidence backing them up], check them out below:
http://videocardz.com/43946/sapphire-radeon-hd-9970-to-feature-12layer-pcb
http://www.xbitlabs.com/news/graphics/display/20130710230935_Sapphire_Begins_to_Evaluate_Next_Gen_AMD_Radeon_HD_Graphics_Card_with_Select_Customers_Report.html
http://wccftech.com/amd-radeon-hd-9970-engineering-samples-shipped-manufacturers/
So... just worth noting, since these are unreleased products, release dates might be pushed back due to manufacturing problems (how many times have we seen this before?), there might be supply shortages (remember 28nm at first?), there might be hardware issues (remember the failing SATA connectors in Intel motherboards?), there might be drivers that might damage the GPUs (nVidia, I'm looking at you)... and these are all rumors, nothing more at this point.
However, it's worth noting that sites which are unreliable don't last long, if they report grossly mistaken rumors very often. Videocardz.com has been right more often than not, though, which leads a certain limited credibility to them. They were right about many of the previous cards, in regards to specs, cooler designs, costs and more.
Anyways, hope this is interesting for ya guys. Seeya.