4k digital signage

Hello guys, maybe im still in time now that you are soon to be making new rig building videos.

Im Looking to build a pc, preferably AMD cpu (either Trinity or FX).  I want to make it the lowest cost posible, mostly because is a digital signage project, i want to know if you guys can help me, whats the minimum ram, the lowest processor speed and what video card with 1 to 4 displayports at the least cost i could find.

The sole purpose for this project is 4k video playback, maybe like what Wendell said, the eyefinity version of the Retina Display Hack.

Thanks again, i wish we could have more Wendell video sections for hardware hacks, and more videos of Pistols games

You're looking for quad 1080p. 

You need ~4 outputs on your GPU(Or am i Horribly misunderstanding and you've already got a 4k display?)

I'd go used on that. The lowest card i can think that's current gen is the 7770. If the sole goal is 4k playback i'd definetely go for a USED PC with a GPU with 4 or more outputs, because pretty much everything reasonable (With 4 outputs)  will be able to playback 4k video.  

 

And if cost is the condition, used would be unbeatable, 2 gigs of ram will suffice. ( dont expect to open more than 20 tabs in chrome tho )