Dual LG 5K on M1 Mini

[Lammers]

Does this work? Dual LG 5K, both Thunderbolt 3, on an M1 Mini? Thanks.

 

[Stephen.R]

No.

 

[Lammers]

That’s what I thought. Thanks.

 

[joevt]

Maybe connect a second LG UltraFine 5K at up to 4K to the HDMI port using a HDMI to USB-C adapter like the Club 3D CAC-1332 (if you have the 27MD5KL model). I'm not sure if anyone has tested that.

 

[Lammers]

Thanks - my LG 5Ks are TB3-only and predate the updated version that supported USB-C natively, so presume that option wouldn’t work.

 

[Amethyst1]

Maybe connect a second LG UltraFine 5K at up to 4K

No offence intended - I've briefly run my Dell UP2715K at 4K and it didn't hold a candle next to native 5K.

 

[joevt]

No offence intended - I've briefly run my Dell UP2715K at 4K and it didn't hold a candle next to native 5K.

Yup. But if you have two LG5K already and an M1 Mac then 4K is the only choice.
Someone did LG 5K at 39Hz but there aren't any HDMI to USB-C adapters yet that support resolution width > 4096. Maybe they'll exist one day: https://insights.club-3d.com/thread/hdmi-2-1-to-usb-c-displayport-1-4-alt-mode/

And the old TB3 only LG 5K (27MD5KA) would also require a Thunderbolt 3 or Thunderbolt 4 add-in card.

And you would need to find a method to override EDID on M1 Mac to enable a 5K39Hz mode since the method used on Intel Macs doesn't work on M1 Macs.

Maybe 4K isn't the only choice - I think some DisplayLink adapters can do 5K to dual cable displays like the Dell UP2715K. I don't know if that works on Macs? For the LG5K (27MD5KA or 27MD5KL), connect the two DisplayPort outputs of the DisplayLink adapter to a Thunderbolt 3 or 4 add-in card.

If the Thunderbolt add-in card idea works there may be issues with the display not turning on sometimes. The USB functions of the display won't work (brightness control, audio, camera, etc.) unless some software (that doesn't exist yet) enables PCIe tunnelling to the Thunderbolt add-in card somehow.

 

[smirking]

Has anyone had any problems with just a single LG 5K? I've got an M1 MBP and an LG 5K and there appear to be some weird stutters that I only notice when I'm hooked up to my external LG 5K monitor.

The stutters I get don't appear to be related to anything processing intensive. I use PHPStorm/WebStorm as a development environment and that mostly runs trouble free with a few exceptions. If I do something that causes a change to the filesystem while I'm plugged into my 5K monitor, the program freezes from anywhere between 1 second and 5 seconds. My Mac doesn't freeze. It's just the program.

There's also a hiccup when I'm not plugged into my external monitor, but it's not so noticeable. It's a little bit laggy performing the same filesystem affecting actions, but it never freezes.