MBP Mid 2015 - 4K Monitor Support?

Hello Barryonyx,

Thanks for using Apple Support Communities. It sounds like you’re looking for more information regarding connecting a display to your Mac. We’re happy to provide some information.

The snippet below comes from the technical specifications for your Mac model:

“Dual display and video mirroring: Simultaneously supports full native resolution on the built-in display and up to 3840 by 2160 pixels on up to two external displays, both at millions of colors

• HDMI video output

• Support for 1080p resolution at up to 60Hz
• Support for 3840-by-2160 resolution at 30Hz
• Support for 4096-by-2160 resolution at 24Hz

You can read more here: MacBook Pro (Retina, 15-inch, Mid 2015) - Technical Specifications

Take care.

Wait! that's not the whole story. Those numbers are for HDMI displays using the built-in HDMI 1.4 port.

According to this new article:

Connect to HDMI from your Mac - Apple Support

But if you connect a DisplayPort family display, you can use MUCH higher resolutions on a single cable:

• Dual display and video mirroring: Simultaneously supports full native resolution on the built-in display and up to 3840 by 2160 pixels on up to two external displays, both at millions of colors
• Thunderbolt digital video output
  • Native Mini DisplayPort output
  • DVI, VGA, dual-link DVI, and HDMI output supported using Mini DisplayPort adapters (sold separately)
• HDMI video output
  • Support for 1080p resolution at up to 60Hz
  • Support for 3840-by-2160 resolution at 30Hz
  • Support for 4096-by-2160 resolution at 24Hz

here is a slightly different take:

2nd Display Support: Dual/Mirroring* 2nd Max. Resolution: 3840x2160 (x2*)

Details:* This model supports a simultaneous maximum resolution up to

3840x2160 on two external displays via Thunderbolt 2.

Alternately, it can support a single display up to 3840x2160 via Thunderbolt 2 and a single 1080p display at up to 60 Hz, 3840x2160 at 30 Hz, or 4096x2160 at 24 Hz via HDMI.

from:

https://everymac.com/systems/apple/macbook_pro/specs/macbook-pro-core-i7-2.5-15-iris-only-mid-2015-retina-display-specs.html

If you had the Discrete graphics model instead (with the R9 370X chip) ThunderBolt/DisplayPort family displays increase to 5K at 60Hz, but HDMI displays stay EXACTLY the same, because this is a limitation of the HDMI 1.4 port on that model MacBook Pro.