Trouble connecting Mac Pro Thunderbolt 2 output to monitor's USB-C input

+1 That adapter is intended to go from a Thunderbolt3/USB-C to Thunderbolt 2/Mini DisplayPort, but even then it's uses in that capacity are limited.

Unfortunately a Thunderbolt 3/USB-C Display, is not the ideal choice for an older 2013 Mac.

What I would do, is test a high quality short Premium Certified HDMI cable with that Display.

Then if I was not satisfied with the HDMI connection? I would return that display and look for one that included DisplayPort input as a third option. Then I would use a Thunderbolt2/Mini DisplayPort to DisplayPort cable.

Whoever told you to use the Thunderbolt 3-to-2 adapter in that way gave you bad advice. It is a bi-directional adapter, but it's only designed for communications between two Thunderbolt devices. It doesn't do extra work needed to take a TB-encapsulated DP signal on one side, and offer up a non-TB-encapsulated DP signal on the other. So,

• If you attach the TB3 side to a modern Mac, and a Mini DisplayPort device to the TB2 side (hoping that the TB2 side will act as a Mini DIsplayPort), it won't work.
• If you attach the TB2 side to an old Mac that has a TB1 or TB2 port, and a USB-C (DisplayPort Alt Mode, non-TB) device to the TB3 side, that won't work, either.

The Dell S2722QC takes USB-C (DisplayPort Alt Mode) input, not Thunderbolt input. The TB2-to-TB3 adapter isn't generating the signal that the Dell S2722QC needs (and wasn't designed to do so).

Hi,

I think it doesn't work that Thunderbolt 2 to USB-C connection, though it could works USB-C to Thunderbolt 2 connection. I'm connecting Mac Pro late 2013 with LCD Cinema Display which has Mini-Display port via Mini Display cable.

Neil Goldberg wrote:

Thank you so much, den.thed ! This is better support than Apple or Dell provided!

You're welcome. We don't have all of the answers. What we have as Apple Product Users is more time behind the preverbal wheel.

Could I trouble you with a follow up question?

Sure and I'll try, with what experience and know how that I have.

I do have the monitor set up with a short HDMI cable and it looks fine to me, but somewhere I had read that HDMI is not ideal.

At this point that is the best option with that setup.

By not connecting via USB-C I realize I'm losing the ability to turn this monitor into a hub. Can you think of any other downsides?

What you need it a second USB patch cable out to the Displays downside USB hub.

The only ones that are clear to me is that I can't choose 60 Hertz refresh with HDMI, only 30 Hertz.

I don't have a straight answer on that one. Resolutions and Refresh rates can very wildly depending on the Mac's GPU, Cable Quality and Display.

I do know for a fact, that a Display with DisplayPort input will allow higher Refresh Rates from a 2013 Mac with ThunderBolt 2/Mini DisplayPort output.

It also seems like the typing is a drop delayed on the monitor but I can't tell if that's a function of the monitor or my CPU or something else.

I suspect that the typing delay, is related to an App or background process that is using a lot of CPU. Maybe open your Activity Monitor and have a look at the CPU usage.

Again many thanks in advance!

No problem, you're welcome.

extremely helpful explanation of why this did not work. Thank you! Based on an earlier posters comment I went ahead and returned the original monitor and got one with both USB-C and DisplayPort outputs and connected it to the Mac Pro with a DisplayPort to Thunderbolt 2 adapter and it’s working fine. Again many thanks!

[Edit: I suggested trying a Mini DisplayPort to HDMI adapter, in case the Late 2013's Mac Pro's Thunderbolt ports – operating in mDP compatibility mode – could generate UHD 4K resolution DP output at 60 Hz. After I posted and the Web page refreshed, I saw that 'shecky200' had simultaneously posted an update making the suggestion moot.]

There is ONE MORE way you could drive that 4K display using the MacPro 2013 desktop and HDMI and get higher refresh rate.

Divide the display area in half and set it up as TWO half-displays, Left/Right. This uses TWO cables at once out of the Mac. Add one more adapter/cable FROM Mini DisplayPort TO HDMI (make sure it works that direction).

On the Mac, set up in Extended Desktop, each display representing the left or right half-display. These are 'Arranged' so that they are concatenated along the appropriate edge.

Provided the display supports Picture-BY-Picture feature (a cousin of Picture-IN-Picture) that can be used to re-assemble the two half-displays into one seamless picture again.

This actually works very nicely, and gets your refresh rate back up to 60 Hz, using two cables, each of which carries half the data.

You're welcome.

Thank you for the suggestion! Yes, I tried that and still couldn’t get better than the 30 Hz refresh rate.

Typing delay is slow on the usb-c monitor, but normal on the macbook monitor !

hum…