I couldn't find an answer to above question a year ago. Now I have my personal experience which I'd like to share here.
Acer Converter Port works as miniDP on my Acer Aspire R7 laptop with Intel HD4000 video adapter. I can work with 2nd external full HD monitor (1920x1080) via miniDP-HDMI adapter - that's in addition to another external monitor via direct HDMI cable. Recently I bought Acer CB280HK 4K 28" Ultra HD monitor and it can work with 4k resolution 3840x2160 up to 32Hz via this miniDP connector using a standard miniDP to DP cable. Note that I can get 4k resolution via HDMI only up to 25Hz.
To set Intel HD4000 to work with 4k resolution via miniDP or HDMI you need to add custom resolution using Intel's CustomModeApp utility - please search internet about how to use it, for ex. Intel site, support forums.
I used basic CustomModeApp mode to set my custom 4k resolutions and it works great - I am really happy with all my office and photo editing apps.
Settings for 4k custom resolutions in basic CustomModeApp mode:
- set resolution 3840 x 2160
- set refresh rate to 25 for hdmi connection and 30 or 32 for miniDP connection
- select "CVT-RB" for the "Timing Standard" dropdown
And below is some more info about custom resolutions from Intel support forum. Good luck!
HDMI : Intel HD4000 Max Pixel Clock supported on HDMI is 225Mhz. So max supported is 1920 x 1080 (60p, 85p) On HDMI Note : 2560 x1440_ (60 Hz) is not supported on HDMI as it Exceeds the max Pixel Clock supported by our Intel 4000 Hardware ( 225Mhz)
DispalyPort : Intel HD4000 Max Pixel Clock supported on DisplayPort is 348 Mhz
So, 2560 x1440_ 60 and 2560 x1600_ 60 is supported on DisplayPort Interface only.
It is possible to do UHD (3840x2160P) using this chip by being careful to stay under the maximum HDMI dot clock. Using CustomModeApp: Front Porch H=48 V=3 Back Porch H=80 V=23 Sync Width H=32 V=5 Active H=3840 V=2160 Scan Rate V=25
It relies on the screen supporting 24Hz refresh rates as most UHD screens will. 24Hz is used by Blue-ray in film mode. Dot Clock for these HDMI settings is 221MHz which is below the hardware maximum of 225MHz
Advice from previous posts Select "CVT-RB" for the "Timing Standard" dropdown