2017 iMac 27" i7 dual display

[Schmidtsk]

Have just ordered iMac 27" i7 4.2Ghz with AMD Radeon Pro 580 GPU for video editing using Avid.

I would like to use a second display for my timeline and bins, and the Retina 5K for full screen playback. I like the idea of an Ultrawide like the LG34UM95 (3440 x 1440) which has thunderbolt. Has anyone tried this combo? USB3-C to Thunderbolt 2 converter would obviously be needed, but would it work? Would the GPU allow the two different resolutions simultaneously, or would the Retina display have to down-rez to HD?

Thanks for any advice.

 

[Anonymous Freak]

As long as you're not mirroring, it works fine. I use my MacBook Pro with a 4K display and two 1080p displays, and each works at its proper resolution perfectly. It's funny, as you drag a window quickly from a "HiDPI" (Retina) display to a "regular" display or vice versa, the window either appears oversized or tiny (depending on which direction you're dragging it,) for a few milliseconds before the OS realizes it has to resize it to or from HiDPI/Retina mode.

And unless you have specific need for that second Thunderbolt 2 port the Thunderbolt version of that monitor provides, save the money and get the non-Thunderbolt version. Just use a USB-C-to-DisplayPort cable (or USB-C-to-HDMI.) If you have other Thunderbolt 2 devices, then sure, go ahead, it's probably worth it to leave your second Thunderbolt 3 port on the iMac itself available. But if you don't need that "outbound" Thunderbolt 2 port on the display, it's just extra money ($100 for the monitor plus the $50 for the adapter.)

 

[EugW]

Here are my results with dual screen, with the adapters used.

https://forums.macrumors.com/threads/dual-imacs.2052555/

I don’t have the issue of window size mismatch for high vs vs low dpi when dragging windows over, not even for a few ms, maybe because the screens are the same physical size and one is a pixel quadrupled version of the other:

5120x2880 and 2560x1440