I have a 16 inch Macbook pro M2 Max.

I currently have a USB C hub that supposedly supports 2 4k monitors. https://www.amazon.com/Anker-PowerExpand-Thunderbolt-Charging-Display/dp/B08RYZJY8M

When I connect them both through the hub, only one of them allows me to set 4K normally, the other one requires me to use scaling.

If I use HDMI on one and USB C on the other then I can do 4K on both.

If I use two USB C ports on the Macbook then I can also do 4K on both.

So is this a limitation of my hub or can I only use one 4K monitor per USB C port?

Thanks.

The MacBook Pro has TB4 ports not USB-C (same plug type, much higher bandwidth). And yes with the proper dock you can run two 4K monitors off of one TB4 port. There are plenty that can support this. Example: Caldigit.

tstafford said:

The MacBook Pro has TB4 ports not USB-C (same plug type, much higher bandwidth). And yes with the proper dock you can run two 4K monitors off of one TB4 port. There are plenty that can support this. Example: Caldigit.

The hub I have (link in the post) says it is thunderbolt 4 and claims to support 2 4k monitors. Just seems odd that it doesn't work.

MntGoat said:

The hub I have (link in the post) says it is thunderbolt 4 and claims to support 2 4k monitors. Just seems odd that it doesn't work.

What type of cables are you using b/w the Mac and the dock and also the dock and the displays?

tstafford said:

What type of cables are you using b/w the Mac and the dock and also the dock and the displays?

Between the Mac and dock I'm using the cable that came with it. Looks like a USB C cable but I guess I don't know what a thunderbolt cable might look like?

The dock to the monitors uses this https://www.amazon.com/gp/product/B07THJGZ9Z

When I've tested using two thunderbolt ports I've used those same USB c to hdmi cables.

I'm not certain and hope that someone else weighs in, but I am concerned that a USB-C cable b/w the mac and the doc is the issue. I think you need a TB4 cable to support two 4K displays at 60Hz. Note: a TB4 cable looks a lot like a USB-C cable but may have a different marking on the connector.

tstafford said:

I'm not certain and hope that someone else weighs in, but I am concerned that a USB-C cable b/w the mac and the doc is the issue. I think you need a TB4 cable to support two 4K displays at 60Hz. Note: a TB4 cable looks a lot like a USB-C cable but may have a different marking on the connector.

That's easy to test. I'll just buy a TB4 cable on Amazon and try it. Thanks.

MntGoat said:

That's easy to test. I'll just buy a TB4 cable on Amazon and try it. Thanks.

I'm optimistic it will work. The TB4 cable carries twice the data of the USB-C (and costs like four times as much!).

So I came back to my office this morning and the little cable itself has the TB symbol and a 4 so I'm guessing that isn't the issue.

Also yesterday I looked at the listing and it has an image that says "doesn't support m1 macbooks" but I assume that is because those don't support multiple external monitors right? but the M2 Max does, right?

Does appear the cable that comes with it is TB4 - so that shouldn't be the issue. Also the site says doesn't support M1 MacBooks (that would seem to refer to machines like the M1 MBA or for that matter the M2 MBA that only support one external display). An M1P or M2P should work.

My advice at this point is to reach out to Anker support. Maybe there's a firmware update or something. Or they can clarify why it doesn't work on a M2P machine that we know supports dual external displays

tstafford said:

The MacBook Pro has TB4 ports not USB-C (same plug type, much higher bandwidth). And yes with the proper dock you can run two 4K monitors off of one TB4 port. There are plenty that can support this. Example: Caldigit.

I also have same problem,your answer help me.

Judy Ma said:

I also have same problem,your answer help me.

Are you using the same hub? I contacted Anker and they said it should be working fine so they had me send it for RMA. We'll see what happens when it comes back.

MntGoat said:

Also yesterday I looked at the listing and it has an image that says "doesn't support m1 macbooks" but I assume that is because those don't support multiple external monitors right? but the M2 Max does, right?

Correct. The MacBooks with the original M1 (not the M1 Pro/Max/Ultra) support only one external display. Same with the MacBook Air M2 (and 13" MacBook Pro M2).

The M1 Pro/Max/Ultra and the M2 Pro/Max (and presumably M2 Ultra if/when it comes out) support at least two external displays, so they're good to go.