I just built a new I7-4970k, 16gig ram, 1tb SSD and NO graphics card just the Intel 4600, driving a Seiki 4k 39" LED LCD, running at 3840x2160. YES full 4k from an intel 4600 ;D. The TV/Monitor was only $349 http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=8430969&CatId=8893 (http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=8430969&CatId=8893) as of 8/11/2014. There ARE some issues documents all over dealing with light lag, and a 30hz max frame rate with a 4k source, as documented other places on the internet. The value for a 39 4k TV/Monitor is good. Just a heads up if you want to try cheap 4k gaming.
lvdata
Ahh... 39". I just asked the size in your support post before reading here :)
That's a good size for 4k. You really need that or larger. The 30hz thing is interesting. I've been wondering what would happen when CW3 ran and the graphic engine could only update the display at 30hz.
I ran a 39" 4K monitor for a little while. The 30Hz was so painful that I ended up abandoning the idea and returning to my regular dual head setup.
Anyway, while I had the 4K monitor going, I did try out CW3 and the experience was nothing short of amazing. I could see vast areas of the map even when fully zoomed in, and the performance was actually quite acceptable. I play with explosions and mist turned off and I'm sure that helped.
The only real downside was that because the monitor was so big you were literally moving your neck to see different parts of the screen. In a game like CW3 that was a lot of moving and you end up with a sore neck pretty quickly.
More options for 4k monitors are starting to open up:
http://www.geek.com/news/philips-is-going-to-ship-a-40-inch-4k-monitor-for-870-1608230/