Samsung Thunderbolt 3 display issue with M1 iMac.

fixed_velocity wrote:

I have a Samsung Thunderbolt 3 display (model LF32TU874VNXGO)

https://www.samsung.com/us/computing/monitors/uhd-and-wqhd/32--tu874-series-lf32tu874vnxgo/#specs

That is a 31.5" monitor with a resolution of 3840x2160 pixels and a refresh rate of 60 Hz. Samsung's site states that it has two Thunderbolt 3 ports, a DisplayPort input, and a HDMI input.

and I can't connect it to my M1 iMac through HDMI or DisplayPort (with an adapter), as I want to free up the display's Thunderbolt 3 connection to my iMac for an extra external SSD. Nothing works, proper cables, Apple adapters.

It sounds like what you are trying to do is to connect to the monitor via its DisplayPort input or HDMI input – then use both of the display's Thunderbolt 3 ports as Thunderbolt 3 expansion ports for your Mac. That is not how it works, and there is no combination of cables that will ever make that work.

The monitor cannot generate Thunderbolt expansion ports out of thin air. If it is to allow (standard) Thunderbolt daisy-chaining on one of its Thunderbolt ports, it must receive a Thunderbolt signal on one of those ports. If all there is in a way of an upstream connection to the computer is DisplayPort or HDMI, that will not carry additional USB or Thunderbolt data, and neither of the Thunderbolt ports on the monitor will have anything to offer to USB drives or Thunderbolt drives that you might plug in.

Samsung does not have any Mac drivers/software on their site but I thought HDMI or DP would just be plug and play universally (Thunderbolt 3 works perfectly, was indeed plug and play, no issues there)

They should be fairly plug-and-play as far as getting a video signal on the monitor – assuming that you are using adapters and cables that support 4K.

They're not going to hook up those two Thunderbolt 3 ports on the monitor to the computer, though. That's not part of any of the DisplayPort or HDMI specifications.

Keith Barkley wrote:

There is plenty of Thunderbolt bandwidth for a display and an SSD. Just get one with a passthrough.

What are you connecting the adapter to? All the connections to an iMac are TB or USB-C with the 4 port model.

The two USB4 / Thunderbolt ports on the iMac are the only ones that carry either DisplayPort Alt Mode signals or Thunderbolt Alt Mode signals.

If the OP substituted a USB-C to DisplayPort or USB-C to HDMI adapter cable for a Thunderbolt 3 cable, the OP wouldn't be "saving" any Thunderbolt ports on the Mac … and the OP would be losing the use of a Thunderbolt daisy-chaining port on the display.

There is plenty of Thunderbolt bandwidth for a display and an SSD. Just get one with a passthrough.

What are you connecting the adapter to? All the connections to an iMac are TB or USB-C with the 4 port model.

It sounds like what you need is a Thunderbolt dock or hub.

Some of those can split a single Thunderbolt chain into several chains ("adding Thunderbolt ports"). This can be convenient if you have Thunderbolt drives that do not have daisy-chaining ports of their own. However, there may still be a limit of six Thunderbolt devices (including the dock or hub) per host port, total.

+1

It sounds like you need a > USB-C Digital AV Multiport Adapter - Apple

It sounds like he was trying to do this.

OP (emphasis mine): "I can't connect it to my M1 iMac through HDMI or DisplayPort (with an adapter), as I want to free up the display's Thunderbolt 3 connection to my iMac for an extra external SSD."

I understand, I am trying to figure out what he did that didn't work.