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srgz

macrumors regular
Original poster
Aug 22, 2010
134
81
I’ve had this monitor for quite some time, but I’ve always used it via HDMI or DisplayPort, which meant running a separate cable to the host for the integrated USB3 hub.

Now that I have an M1 Mac Mini, I figured it’s a good time to actually try using the thunderbolt capability — one cable for both the monitor and the hub, awesome!

It works…except the monitor’s integrated USB hub is now running at USB2 speeds…which doesn’t seem right to me.

Interestingly enough, I can use the monitor’s second (downstream) thunderbolt port to connect / daisy chain a separate USB3 hub, using a type-c to Micro-B3 cable I got from Amazon, and that hub runs at full USB3 speed, even through the single thunderbolt connection to the host.

So this seems like something that should not be happening…anyone have any suggestions?

I tried the Asus tech support chat and they were pretty useless, shocker…I don’t think the fellow even understood the problem I was describing.
 

rmgbenschop

macrumors member
Dec 5, 2020
54
34
Did you check the OSD for some sort of USB speed setting?

I can remember the same setting on my old monitor where you had two settings, one which prioritise display resolution which put the usb hub to 2.0 speeds and one which prioritise usb speeds which limits the resolution and put the usb hub to 3.0 speeds.
 

srgz

macrumors regular
Original poster
Aug 22, 2010
134
81
Did you check the OSD for some sort of USB speed setting?

I can remember the same setting on my old monitor where you had two settings, one which prioritise display resolution which put the usb hub to 2.0 speeds and one which prioritise usb speeds which limits the resolution and put the usb hub to 3.0 speeds.
No dice. No option for the USB hub in the OSD. I’m not sure why it would have any effect on resolution, though.

There should be more than enough bandwidth for 4K60 at 10 bit RGB / 4:4:4 with HDR and a USB3 hub with Thunderbolt 3/4.

I believe a single 4K60 HDR with 10-bit RGB stream is 15.68 Gb/s

Maybe with older DisplayPort / Thunderbolt versions it was an issue ?‍♂️

If I had to bet on it, I’d say it’s probably a bug with the monitors firmware…argh. This is going to take forever to even be able to talk to someone at Asus that even knows what a mac is.

Might as well just work around it for now…the downstream hub works great.
 

SadBoy Pro

macrumors member
Jan 3, 2016
54
33
UK
No dice. No option for the USB hub in the OSD. I’m not sure why it would have any effect on resolution, though.

There should be more than enough bandwidth for 4K60 at 10 bit RGB / 4:4:4 with HDR and a USB3 hub with Thunderbolt 3/4.

I believe a single 4K60 HDR with 10-bit RGB stream is 15.68 Gb/s

Maybe with older DisplayPort / Thunderbolt versions it was an issue ?‍♂️

If I had to bet on it, I’d say it’s probably a bug with the monitors firmware…argh. This is going to take forever to even be able to talk to someone at Asus that even knows what a mac is.

Might as well just work around it for now…the downstream hub works great.
I know this is a really late reply to this. I also have the PA32UCX and have just been calibrating it using the ASUS ProArt Calibration software on my PC with the USB-C downstream connected. Following calibration I connected my M1 MacBook Pro and... no dice!

I disconnected the downstream connection to the PC and instantly the Thuderbolt connection engaged! Everything in the USB-A works at full speed as far as I can tell.
 
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