I have a 15" mid-2014 MBP (NVIDIA GeForce GT 750M 2048 MB). It is currently running two external monitors, a 4k and an HD (1920 x 1080), both at 60 Hz refresh.
I'd like to know if it can instead run 4k + QHD (2560x1440 or 2560x1600), also at 60 Hz refresh.
There have been other questions about running multiple monitors with a mid-2014 MBP:
mid-2014 rMBP multiple monitors
Running 3 External Monitors off a Mid 2014 MacBook Pro
But none specifically addresses the question of whether it can do 4k + QHD.
Also, if it can run the QHD, can I connect it via HDMI, or would I need TB?
I'd prefer to hear from someone who is (or has tried to) actually run both a 4k and QHD on a 15" mid-2014 MBP w/ the above-listed graphics card.
UPDATE, 4/1/20:
I now have the MPB driving three external monitors: 4k, WUXGA (1920 x 1200) and HD (1920 x 1080). Given this, I expect it would have no problem driving 1 x 4k and 1 x QHD, since 1 x WUXGA + 1 x HD has more pixels than 1 x QHD (I'm assuming equal color depths, as is the case here):
[(1920 x 1200) + (1920 x 1080)]/(2560x1600) = 1.06875, and
[(1920 x 1200) + (1920 x 1080)]/(2560x1440) = 1.1875
Here's a screenshot from the Graphics/Displays section of the System Information report: