I just received the GTX 1080 card (08G-P4-6180-KR) and installed. It is working quite well with my LG 4K monitor using the HDMI interface. I have ordered another HDMI monitor but just realized my card only has one HDMI port. The graphics card has 3 additional Display ports and a DVI-D port.
 
How or what do I use to connect another HDMI monitor? Or, what interfaces with the Display ports?
 
Thanks,
 
Merle
 
 

Just get a dp to hdmi connector. I do the same with my monitors

For 4K 60Hz resolutions, you need an ACTIVE adapter or you won't be able to get 4K 60Hz.
 
Like this one: https://www.amazon.com/DisplayPort-HDMI-2-0a-Active-Adapter/dp/B01B6ZOMIS/ref=sr_1_1?ie=UTF8&qid=1478901385&sr=8-1&keywords=DP+to+HDMI+4K+60Hz 

You'll need to buy a displayport to hdmi adapter. I'd recommend this one.

Thanks for the info. Didn't realize there was an adaptor