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New MacBook Pro Supports Up to Two External Displays With M1 Pro Chip, Up to Four With M1 Max Chip
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I want to know if it will do extended desktop on 3 external monitors via a traditional USB C Dock that has 2 HDMI and a DP on the dock that plugs in to 1 TB 4 port. MST I believe is required for that. Mine won't be to me until 1st week in December.
Uh no. It’s not crazy at all. The HDMI port is there for convenience. Not for niche 4K 120 use cases.
Thunderbolt should support 2 displays per port. However, we had the original M1 Mac problem where the second Thunderbolt connection of a Thunderbolt port was only usable when connecting a dual tile display such as the LG UltraFine 5K or Dell UP2715K or similar. We'll have to test if this has been improved to allow two separate displays for a single Thunderbolt port.
There are 3 Thunderbolt ports. So not all of them can use 2 displays at once (if any can).
Apple probably still doesn't support MST for multiple displays. I don't see why they would change that for M1 Macs. It may support MST for dual tile single DisplayPort cable 4K displays but I don't recall if someone tested that with M1 Macs. 4K MST displays were released before 4K SST displays.
M1 Macs support USB-C DisplayPort Alt Mode using DisplayPort 1.4 so 4K120 should be possible. It depends on Apple's drivers. 4K120 is fewer pixels than 6K60.
Apple rarely says what version of DisplayPort it supports. Google finds two occurrences of DisplayPort 1.4 at support.apple.com
https://support.apple.com/en-ca/guide/imac/apd2e7352054/mac
https://support.apple.com/en-us/HT208897
It's like Apple won't say it supports DisplayPort 1.2 because they don't support MST which was added to DisplayPort 1.2...
Agreed that it’s disappointing there’s seemingly no 8K output support. So you can edit 8K videos in Final Cut Pro but can’t see them in all their glory??
Also, isn’t Thunderbolt 4 supposed to support 1 8K display at 60hz?
Also, isn’t Thunderbolt 4 supposed to support 1 8K display at 60hz?
If I were to buy a Thunderbolt to HDMI 2.1 converter with an HDMI 2.1 compatible cable, and plugged an M1 Max laptop into an HDMI 2.1 compatible TV, would it be able to push 4K @ 120hz?
Does anyone know if running 3 4k displays will be possible with the M1 Pro?
The old MBP 16 could run 2 6k displays or 4 4k displays. Given the bandwidth of 2 4k displays is less than the bandwidth required for one 6k display - surely it would be possible?
The old MBP 16 could run 2 6k displays or 4 4k displays. Given the bandwidth of 2 4k displays is less than the bandwidth required for one 6k display - surely it would be possible?
Apple said previous M1 Macs only support Thunderbolt/USB4. They could not call them Thunderbolt 4 because that requires being able to connect two 4K displays to the same port.
Since Apple says the M1 Max and M1 Pro support Thunderbolt 4, then all their Thunderbolt ports must support two displays. That also means an LG UltraFine 5K should be able to connect to any of those Thunderbolt ports. So for the M1 Max, the question is, what combination of ports can support two displays? Is it two per side, or can one side have 4? I wonder if more than two displays can be connected to a single Thunderbolt port (probably not - all previous Thunderbolt controllers have only ever had up to two DisplayPort inputs).
As far as I know TB4 is 40 Gbps of bandwidth and HDMI 2.1 is 48 Gbps. So no matter what you do it will not be equivalent.
But you don't need 48 Gbps for 4K120.
For displays, TB4 uses DisplayPort 1.4 which is 25.92 Gbps without the the 8b/10b encoding since Thunderbolt has its own encoding of 64b/66b. Actually, Thunderbolt is 41.25 Gbps on the wire (takes 66 bits on the wire to transmit 64 bits of data). USB4 is similar to Thunderbolt but it uses 128b/132b encoding and 40 Gbps on the wire so it can do 38.8 Gbps of data.
HDMI 2.1 is 42.67 Gbps if you remove the 16b/18b encoding.
It doesn't work on an M1 with the current version of Monterey I've tried (Club-3D CAC1085 and also a Sabrent adapter - https://www.amazon.com/Sabrent-Func...08Y246V8X/ref=cm_cr_arp_d_product_top?ie=UTF8). Both adapters work on a windows PC with the same display, and MacOS works with some 4k 120hz / 144hz Display Port monitors - so it's likely a compatibility / software issue. I really hope it will work on the M1 Pro / M1 x, but I'm guessing it won't.
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Thunderbolt (3 and 4) allocate three separate streams within the 40 mbit/s pipe. The first two streams are for display data and take priority. Each stream can allocate up to a maximum of 22 mbit/s but only up to the remaining data after the higher priority stream has taken it's allocation. The cap of 22 mbit/s seems to have been related to a decision by Intel make sure that a 2 port controller connected to a 4x PCIe providing only 32 mbit/s would always have enough bandwidth for a display on one port and a full speed 10 mbit/s USB C connection on the second port, as the bandwidth and streams are shared between all the ports on the Thunderbolt controller. Remember the early Thunderbolt controllers never actually delivered the full specification performance except in the highest cost SKUs. This is why the data stream on a Thunderbolt controller never passes more than 22 mbit/s even if there are no display's attached to any of the ports.
I'm expecting based on Apples slides that the M1 PRO will have two controllers likely split between the HDMI port/thunderbolt on one side and the the two thunderbolt ports on the other side. The M1 MAX will most likely have 3 controllers with HDMI shared with one of them. Three controllers would have enough throughput to do the 3 6k displays plus a 4k HDMI port assuming the HDMI was limited to 4k 4:2:2. It is possible the HDMI port will have a dedicated graphics controller but I doubt it.
us.targus.com
I'm expecting based on Apples slides that the M1 PRO will have two controllers likely split between the HDMI port/thunderbolt on one side and the the two thunderbolt ports on the other side. The M1 MAX will most likely have 3 controllers with HDMI shared with one of them. Three controllers would have enough throughput to do the 3 6k displays plus a 4k HDMI port assuming the HDMI was limited to 4k 4:2:2. It is possible the HDMI port will have a dedicated graphics controller but I doubt it.
Thunderbolt 3 USB Type-C
Thunderbolt 3 can also supply up to 100W of power on the USB Type-C connection, but doesn't have to support power at all. Thunderbolt 3 brings Thunderbolt to USB-C at speeds up to 40 Gbps, creating one compact port that simultaneously supports high video and data bandwidth and power on a single...
us.targus.com
Isn’t the only 48gbps output like 12bit 4:4:4 8k60 or something? Basically anything else is under 40 no?
which is the entire reason almost all the 2.1 ports are 40 not 48 for now? Heck, my LG C9 has 48gbps ports, but the 2 years that followed only had 40gbps ports. But I’d still take the newer implementation cause the old one is doing some really weird stuff using multiple chips at lower speeds to like split the signal vs the new ones where the chip can actually natively switch 40gbps video signals.
not that you can actually tell the difference in use. For 4K, 40 vs 48 is 100% irrelevant.
The strangest part about using hdmi 2.0 here is just that they were able to put 2.1 in the cheap apple tv but not the “pro” laptop.
Either way, they seem impressive to me, and I do want one, but the entry price is steep enough to stick with my 13” for another year and see what the 2022 ones are like.
which is the entire reason almost all the 2.1 ports are 40 not 48 for now? Heck, my LG C9 has 48gbps ports, but the 2 years that followed only had 40gbps ports. But I’d still take the newer implementation cause the old one is doing some really weird stuff using multiple chips at lower speeds to like split the signal vs the new ones where the chip can actually natively switch 40gbps video signals.
not that you can actually tell the difference in use. For 4K, 40 vs 48 is 100% irrelevant.
The strangest part about using hdmi 2.0 here is just that they were able to put 2.1 in the cheap apple tv but not the “pro” laptop.
Either way, they seem impressive to me, and I do want one, but the entry price is steep enough to stick with my 13” for another year and see what the 2022 ones are like.
A Thunderbolt DisplayPort stream can be up to 25.92 Gbps. Two DisplayPort streams can add up to a max of 34.56 Gbps but an XDR display can go beyond that using two DisplayPort streams of 19.5 Gbps (if DSC is not supported).
I've seen benchmarks that show over 3000 MB/s (24 Gbps) so the cap can be 25 Gbps. A discrete Thunderbolt controller has never allowed near 32 Gbps of data (31.5 Gbps after considering 128b/130b encoding) or even 3500 MB/s (28 Gbps - the max speed of a gen 3 NVMe). Even if you raid two Thunderbolt ports of the same controller (tested with Titan Ridge), the speed does not exceed 25 Gbps.
An integrated Thunderbolt controller doesn't use real PCIe between the CPU and the controller because the controller is inside the CPU so it's not limited to 31.5 Gbps. In that case you can get more than 25 Gbps from any two ports (MacBook Pro with Intel Ice Lake CPU for example gets ≈39 Gbps from two NVMe connected to any two ports).
It seems to me that with an integrated Thunderbolt controller, it should be possible to connect two NVMe to the same Thunderbolt port, each one connected to a separate Thunderbolt controller, and get more than 25 Gbps up to ≈38 Gbps (use a RAID 0 or ATTO Disk Benchmark.app). It should be possible because the upstream of the integrated Thunderbolt controller is not real PCIe, and only the downstream PCIe connection between the Thunderbolt controllers and NVMe is limited by real PCIe. The upstream connections of the Thunderbolt peripherals is 40 Gbps Thunderbolt (not real PCIe again). I have not seen this tested - we know that Ice Lake can do ≈39 Gbps from any two ports but have not repeated the test using a single port for the two devices.
The M1 PRO and M1 MAX have the same number of ports so I assume they have the same number of controllers. What's different is the number of connections to the GPU. Assuming two DisplayPort inputs per controller (like with discrete Thunderbolt controllers), you only need two controllers for three XDR displays (M1 and XDR support DSC so only 15.4 Gbps is required for each display). They'll have some DisplayPort mux arrangement so that the limited DisplayPort connections to the GPU can be switched to whatever ports have displays connected (up to two per port).
Don’t forget that is one of the few actual differentiators for real TB4, a slightly higher total capacity for the DATA channel.
But he is also correct. The actual TB3 standard at least had specific allocations for DisplayPort AND USB 3.0 or 3.1 (so 5 or 10gbps). Basically they treated TB3 more like an extension of USB-C like USB-PD and DP Alt Mode. The entire TB channel is basically bolted on top. Obviously it’s way more complex than that in reality because it’s all done through the Thunderbolt encoding and whatnot.
TB4 if I recall correctly improved 2 things, it can use a more efficient compression of the video streams, and it allocated more potential bandwidth the TB data channel, I believe by conditionally swapping the USB channel‘s allocation to part of the TB channels. And since they now allow hubs for TB and usb controllers are cheap, it’s easier for them to just build the usb host into the endpoint and then convert that data to be passed through the TB data channel instead.
TB3’s potential data transfer rate is ~22Gbps just for data, TB4 I believe increased that to 26? But yes to your question, if for example you used 2 of the Atto link 25gbps or 40gbps nics (they expensive) on two separate controllers (that was one of the few ”upgrades” the 2port MacBooks at least the M1 pros had, is they still have 2 TB controllers each with their own “x4” channel tho who knows how that works inside their specific implementation since they are building their own chips AND tb/usb controllers so they can conceivably talk all sorts of different ways), using SMB multichannel you should be able to manage 44 gbps minus whatever overhead is there (I assume that’s where your 39gbps comes from).
I’m not sure if softraid has enough perf to fully take advantage, but I also haven’t tested it. Depending on efficiency, it conceivably could do the same thing if you stripes across a pair of drives.
My assumption for why they stuck that stupid 2.0 port in the mbp when they have 2.1 chips as seen in the atv is because they assumed people would be more interested in 2 external 4K displays for the lowest model over a single higher performing one. I’d also imagine it is technically capable of doing 120hz with a usbc->2.1 adapter, but it’s likely not supported in software currently because apple doesn’t make any external 120hz displays. still a stupid choice tho.
The most likely time for when they could implement 120hz external will be when they update/replace the XDR display. The other somewhat interesting prospect for me, is they could conceivably build “smart monitors” where they actually basically build an internal gpu into the display. From what I recall, the XDR display already has like an a-series chip powering it lol.
What I really hope is apple eventually tries to replace TB with a copper/fiber hybrid cable that can actually go faster. They can already push 100+gbps over a fiber pair 100+ft on cheap fiber. The only reliable active TB cables I’ve found so far are the apple pro cables. Double the price of the others. But they have way better (much tighter snap and reliability) connection than any of the others I’ve tried. The copper of course would be for power and not much else.
Sure it might be possible to push more over copper, but you are gonna need a ridiculously shielded and grounded and massive bandwidth cable like gross Cat-7/8. Plus half the reason 10gbe took so long to trickle down is pure heat output. Optical is just so much more efficient, and with the “plastic” fibers that are nearly as good and much more flexible now available, there is just no reason to stick with wires. Photonics would be best, but probably 20+ years out for that to be mass market viable… if ever.
As to the few complaining about the lack of external gpu support… kinda seems unnecessary given the horsepower of the GPU it has. Games can’t tell the difference anyway since it would the same metal apis. I’m very curious to see what devs will actually be able to get running on the new MacBooks. I’m still gonna hold out to M2 or w/e to upgrade my laptop, but I look forward to the next Mac mini or perhaps lil’ Pro if that happens.
But he is also correct. The actual TB3 standard at least had specific allocations for DisplayPort AND USB 3.0 or 3.1 (so 5 or 10gbps). Basically they treated TB3 more like an extension of USB-C like USB-PD and DP Alt Mode. The entire TB channel is basically bolted on top. Obviously it’s way more complex than that in reality because it’s all done through the Thunderbolt encoding and whatnot.
TB4 if I recall correctly improved 2 things, it can use a more efficient compression of the video streams, and it allocated more potential bandwidth the TB data channel, I believe by conditionally swapping the USB channel‘s allocation to part of the TB channels. And since they now allow hubs for TB and usb controllers are cheap, it’s easier for them to just build the usb host into the endpoint and then convert that data to be passed through the TB data channel instead.
TB3’s potential data transfer rate is ~22Gbps just for data, TB4 I believe increased that to 26? But yes to your question, if for example you used 2 of the Atto link 25gbps or 40gbps nics (they expensive) on two separate controllers (that was one of the few ”upgrades” the 2port MacBooks at least the M1 pros had, is they still have 2 TB controllers each with their own “x4” channel tho who knows how that works inside their specific implementation since they are building their own chips AND tb/usb controllers so they can conceivably talk all sorts of different ways), using SMB multichannel you should be able to manage 44 gbps minus whatever overhead is there (I assume that’s where your 39gbps comes from).
I’m not sure if softraid has enough perf to fully take advantage, but I also haven’t tested it. Depending on efficiency, it conceivably could do the same thing if you stripes across a pair of drives.
My assumption for why they stuck that stupid 2.0 port in the mbp when they have 2.1 chips as seen in the atv is because they assumed people would be more interested in 2 external 4K displays for the lowest model over a single higher performing one. I’d also imagine it is technically capable of doing 120hz with a usbc->2.1 adapter, but it’s likely not supported in software currently because apple doesn’t make any external 120hz displays. still a stupid choice tho.
The most likely time for when they could implement 120hz external will be when they update/replace the XDR display. The other somewhat interesting prospect for me, is they could conceivably build “smart monitors” where they actually basically build an internal gpu into the display. From what I recall, the XDR display already has like an a-series chip powering it lol.
What I really hope is apple eventually tries to replace TB with a copper/fiber hybrid cable that can actually go faster. They can already push 100+gbps over a fiber pair 100+ft on cheap fiber. The only reliable active TB cables I’ve found so far are the apple pro cables. Double the price of the others. But they have way better (much tighter snap and reliability) connection than any of the others I’ve tried. The copper of course would be for power and not much else.
Sure it might be possible to push more over copper, but you are gonna need a ridiculously shielded and grounded and massive bandwidth cable like gross Cat-7/8. Plus half the reason 10gbe took so long to trickle down is pure heat output. Optical is just so much more efficient, and with the “plastic” fibers that are nearly as good and much more flexible now available, there is just no reason to stick with wires. Photonics would be best, but probably 20+ years out for that to be mass market viable… if ever.
As to the few complaining about the lack of external gpu support… kinda seems unnecessary given the horsepower of the GPU it has. Games can’t tell the difference anyway since it would the same metal apis. I’m very curious to see what devs will actually be able to get running on the new MacBooks. I’m still gonna hold out to M2 or w/e to upgrade my laptop, but I look forward to the next Mac mini or perhaps lil’ Pro if that happens.
Yeah I suspect this too. The PC community is generally “we’ll give you the best functionality we can and you go figure out how best to use it”, while Apple does “we give what best integrates with our own ecosystem, even if there are better products out there”. Those that love and stick to the Apple ecosystem won’t have any problems, but power users that pick and choose products are left disappointed!
I hope you're correct. I really want to replace my Intel iMac + 2 1080p external setup at work with one of the new MBPs, but I don't want to lose the iMac screen size.
No way I'm convincing the boss to spring for an M1 Max just for that, and rightfully so.
Well Apple fully solved the product being the bottleneck. Now we just need the tools (not me but developers) to really be created to take full advantage of the processor, gpu and shared memory architecture.
I know I loathe seeing others write similar posts (in a negative light) but it's fitting in a positive light here.
"These things are going to SING!"
- Steve Jobs.
According to the Caldigit Element Hub specs, it supports 2 x 4k60 monitors off a single TB4 port on M1 Pro and M1 Max
Thunderbolt 4 | USB4 | Element Hub | CalDigit – CalDigit
www.caldigit.com