2015 15" rMBP with Iris graphics--what 4K/5K displays will work?

[cmm]

I have a 2015 rMBP with Iris Pro graphics (no dedicated gpu), what options do I have to run an external 4K or 5k monitor at a hidpi scaled resolution (either 1800, ~1600 or 1440. Is this possible? Thanks in advance!

 

[LiE_]

4K, 5K requires discreet GPU from that model.

 

[cmm]

Really? Wow. So the Dell P2715Q won't work on this model?? What happens when you try to hookup the P2715Q? Hopefully apple adds some discrete GPU models to the refurb store soon, otherwise I'll have to purchase the new 15 MBP :/ Where else is a reliable place to find refurb or slightly discounted but newish macs besides the refurb store, which is really dry right now....

 

[cmm]

Well, not sure what you are talking about lifeisepic, but for anybody else interested, I bought a Dell P2715Q today and plugged the mDP cable in my 2015 15" rMBP with 16gb ram, 500gb ssd and Iris Pro graphics and the Dell turned on immediately, with no hesitation. No flickering, no issues, both in clamshell mode and running the laptop display as well. Using SwitchResX, I decided to use the ~1900 HiDPi scaled resolution and can't be happier!

 

[LiE_]

I said you cannot drive a 5k monitor at 5k, but you have bought a 4k monitor so I'm not sure what your response is about?