Can the M4 Pro macbook pro support 3 displays in clamshell mode?

the only one that has changed is M4 (Palin)

The same rules we learned for the M1 and M2 and M3 mostly still apply to the M4 models. Display interfaces are generated deep inside the system on a chip. How many there are depends on the exact type of Processor:

M3 (plain) like the 13-in and 15-in supports up to ONE External fully hardware-accelerated external display.

Except the M3 MacBook Air models with 13 or 15-in display, (and certain M3 plain MacBook Pro models when running 14.6 or later) which can support a second external display instead of the built-in display when you close the cover on the built-in display. This may require MacOS 14.6 or later.

M4 (plain) supports up to Two fully hardware-accelerated external displays (three for Mac mini)

M4 PRO processor supports up to Two fully hardware-accelerated external displays. (three for Mac mini)

M4 MAX processor supports up to Four fully hardware-accelerated external displays.

M4 ULTRA processor supports up to Eight fully hardware-accelerated external displays

Tech Specs now available here:

MacBook Pro - Tech Specs - Apple

MacBook Pro - Tech Specs - Apple

bijnori wrote:

M4 pro macbook pro can support 2 external displays, but can it support 3 in clamshell mode?

I assume the answer is No.

The only Apple Silicon Mac notebooks that support an extra "lid closed" display are MacBook Airs and Pros with a plain M3 chip. Without the ability to redirect one of the two video outputs of their plain M3 chip, they would not be able to drive a second external display at all.

Mac notebooks with Pro and Max chips have always been able to drive at least two external displays when the lid is open, so they had much less need for extra logic to be able to redirect one of the chip's video outputs.

If you need or want to drive three external displays, buy a MacBook Pro with a Max chip.

Grant Bennet-Alder wrote:

this just published today:

How many displays can be connected to MacBook Pro - Apple Support

That article appears to contradict Apple's Technical Specifications – and not in a good way.

The Technical Specifications say that these MacBooks can drive two external displays with the lid open.

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M4 and M4 Pro

Simultaneously supports full native resolution on the built-in display at 1 billion colors and:

• Up to two external displays with up to 6K resolution at 60Hz over Thunderbolt, or one external display with up to 6K resolution at 60Hz over Thunderbolt and one external display with up to 4K resolution at 144Hz over HDMI
• One external display supported at 8K resolution at 60Hz or one external display at 4K resolution at 240Hz over HDMI

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The new article, to which you linked, says

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MacBook Pro with M4 chip or M4 Pro chip

…

Supports two displays in any one of these configurations with lid closed

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Hopefully a cut and paste error.

Re: “Wow, this article further downgrades M4 pro MacBook pro capability to drive 2 external displays.”

What do you mean by “further downgrades”? The capability outlined in the Technical Specifications for the M4 Pro MBPs is not a downgrade from the capabilities of the previous M1 Pro, M2 Pro, and M3 Pro MBPs. IIRC, all of those could drive two external displays and the built-in one at the same time. Three external displays has consistently required a MBP with a Max processor.

this just published today:

How many displays can be connected to MacBook Pro - Apple Support

.

Grant Bennet-Alder wrote:

Which flavor do you think is correct? I would guess tech specs?

It appears so. After I reported the inconsistency, there was an update to

How many displays can be connected to MacBook Pro - Apple Support

No more "with lid closed" language in the "Two external displays" part of the "MacBook Pro with M4 chip or M4 Pro chip" section. Now the language is consistent with the Technical Specifications – which have always stated that you could use the two external displays with the lid open.

For MBPs with a plain M4 chip, this represents a definite upgrade over the rules that have previously applied to any Mac notebook with a plain M-series chip.

Grant Bennet-Alder wrote:

Which flavor do you think is correct? I would guess tech specs?

I would think so.

The Technical Specifications for Mac minis and high-end iMacs with the plain M4 chip are evidence that the chip can drive three displays (total). The writer of the new Support article may have been thinking of the rules for the plain M3 chip – which appears to be limited to two active displays (total).

The {M1,M2,M3} Pro MBPs have always been able to drive two displays with the lid open.

rmbrown09 wrote:

Do you think the base or Pro M4 chip can support two 240hz 1440p displays? It’s less bandwidth than 144hz 4k.

What about 360hz? It’s also less bandwidth..

Trying to find any information on dual high refresh rate displays.

The specifications imply that you can attach one display with a refresh rate of 240 Hz, and that this comes at the expense of losing a display output.

So if you attach a 240 Hz display to a MBP with a plain M4 or M4 Pro chip, the specifications imply that this is the only external display you can have. If you attach it to a MBP with a M4 Max chip, they imply that you can have up to two additional 60 Hz displays.

Do you think the base or Pro M4 chip can support two 240hz 1440p displays? It’s less bandwidth than 144hz 4k.

What about 360hz? It’s also less bandwidth..

Trying to find any information on dual high refresh rate displays.

be sure to let them know in Product feedback pages:

Product Feedback - Apple

Which flavor do you think is correct? I would guess tech specs?

There is nothing in the specifications that says, or implies, that you can have even one 360 Hz display.

Coming back to this, tested on the base MBP M4, and can run 360hz off the HDMI.

Have cable coming tomorrow to see if I can do dual 360hz, one via HDMI and one via USB-c to HDMI.