GPU for 2x4K monitors

I just bought 2x 4K monitors both with displayport.

I need to get a new graphics card. I'm not expecting to be doing heavy gaming on here so would rather something cheap and quiet over something noisy and expensive.

Basically, what's the cheapest graphics card that will handle 2x 4K monitors? I don't mind paying a little more if there is a big spike in price/performance but I really don't want to spend more than £100 and would prefer it to be as quiet as possible (passive cooling even?)

This is miniDP or normal?

from what I've seen most recent videocards have miniDP and will need an adaptor which isn't a big deal really.

I can't seem to find any with x2 DP

ususally I find DP/HDMI/DVIx2 or HDMIx2

I will have a further look.

In reply to a post by epyon:

I can't seem to find any with x2 DP

Here's a couple with dual mini DisplayPort -

http://www.ebuyer.com/663138-msi-r9-280-gaming-3gb-g...

http://www.ebuyer.com/663139-msi-r9-270x-gaming-itx-...

What monitors did you get? Think I'm going to wait for 35-40" 4K displays to drop in price before switching(Philips have just launched a 40" 4K monitor for £600, so prices should fall from there).