Apple's Pro Display XDR takes Thunderbolt 3 to its limit
fabiensanglard.net
fabiensanglard.net
Edit: this problem only seems to happen on Intel, not Apple silicon machines.
Can't, or won't? M1 MacBook pros for some reason can't do 4k120 over hdmi unless you buy a specific usbc-hdmi adapter and fool it into thinking it's displayport (or something like that, I'm paraphrasing. You can find info if you search for cablematters DDC 4k120 m1.)
I went deep on this last night shopping for a cable
USB-C/DP to HDMI adapters often need to do some amount of rewriting EDID information because they need to be transparent to the host computer and the display, so it's the adapter that's responsible for ensuring that modes that cannot be handled on both sides of the adapter are not advertised to the PC. When you layer that complexity on top of the existing minefield of ill-conceived EDID tables widespread in monitors, on top of the limitations of macOS (limited special-case EDID handling, little to no manual overrides/custom mode settings), it would be more surprising if there weren't some common use cases that theoretically ought to work but are simply broken. Applying the necessary EDID patch via adapter firmware is simply the easiest option where macOS is involved.
Even on Windows with a DP cable directly from GPU to display it's not all that rare to need a software override for EDID in order to use modes that ought to work out of the box (eg. I have a recent Dell monitor that cannot simultaneously do HDR and variable refresh rate out of the box).
Is the problem expressing the maximum supported bandwidth end-to-end, i.e. not as a function of the DP channel quality that the source sees?
I have fixed the article and added a footnote to this comment.
Meanwhile, Apple wants $70 a pop for a single, 1m Thunderbolt 4 cable, and that's only been increasing. What will Thunderbolt 5 be? Corning and I think one other briefly did optical Thunderbolt cables, but those were $500-1000. Whereas premade quality duplex OM4 with helical steel armor runs more like $2.20/meter.
Feels like we somehow ended up in a yet another technology path dependent evolution path where decisions that saved a bit at the time have then imposed major costs forever more :(. Man it'd be so cool to just be able to run a screen and input boxes hundreds of feet away from a workstation for $60, or have an $8-12 cable be good for decades of evolution in bandwidth barring regular wear (and when it's that cheap who cares even if it breaks after 5 years?), or be able to route displays/TVs and PCIe and whatever else around like any other networking with no compromises. Sigh.
Are these used for very long runs - as in a video source to a projector (via hdmi) hundreds of meters away, like in a stadium..?
Thank you!
If you want to go 15-30m--- using a video source from another part of your house, or to drive a projector in the middle of a classroom--- and you buy an "active cable", odds are it's fiber optic inside.
If you want to go hundreds of meters away, you'll get a purpose-built box that uses your own optical cables instead of a cable that hides the optical transceivers inside.
- long runs that are not that long. hdmi does not like long cables at all. even an overhead projector in a classroom requires super expensive cables (ever wondered why it's still mostly vga?)
- packing multiple displays in a single cable. fiber is so thin that with trunk cables you get a lot of strands in a single cable, capable of running a lot of displays
- just getting a really thin cable that can be run in existing conduits or hard to reach places
I did buy such a cable for home for the third reason, to run from the PC in the office to the TV in the living room. It runs on a bog standard OM3 MPO cable. The specific one I got comes from HeyOptics and their website already showcases a few usecases [1]. (not affiliated, just a great product that just works)
As for stadiums and more generally broadcast video, they're using SDI instead of HDMI. Those are indeed most of the time fiber, both for range and weight (think of the cameraman running along the terrain during a sport event, and their long tail of cables). When they use HDMI it's more in the control room.
[1]: https://www.heyoptics.net/products/8k-hdmi-mpo-optical-cable
(edit: fixed list formatting, I always forget this is not markdown)
HDMI and DisplayPort are good for a bit longer than Thunderbolt over copper, but not by all that much. HDMI 2.1 can only go to around 3m as well now.
So we're in a world where "long" is a mere 5 meters / 15 feet. This is why so many VR headsets are using fiber cables - it has to be long to enable the movement and logistics of connecting a PC to someone freestanding in a room, but modern video signals are just too hard to drive over copper at that not really that long distances.
Eh? Typical min bend radius is like 10x diameter in static conditions, so for a 2mm fiber cable that'd be 20mm or ~0.8". That's not an issue at all with consumer usage, and if you're really worried is trivially solved by just building the thing up to the level of thickness Thunderbolt cables have already. That's why Corning for example advertised their old TB optical cables as "zero bend radius" [0], adding more polymer/armor around a fiber cable so that someone can do whatever with it and it naturally won't go out of spec isn't a big deal.
FWIW, anecdotally high performance copper doesn't like abnormal use either. 10g USB-C cables are cheap enough that I tried taking one and using a vice grip to actually really squash thing at an angle, and it didn't like that at all in terms of working reliably afterwards. I doubt DP, HDMI and the like would do better, and those are plenty thick too. It never comes up though in normal use. And when cables are cheap vs stupid pricey making a mistake no longer is such a big deal. If you use an $8 cable a bit too hard and it stops working, well grab another one out of the drawer. If your $70 cable breaks that's a touch worse.
----
0: https://www.corning.com/microsites/coc/ocbc/Documents/CNT-00...
I’ve been involved in the replacement of two fibre optic cables at work, used for pulse oximetry in an MR scanner. It was very expensive, twice.
People force a bend and destroy them. It doesn’t matter what you tell people, they break them.
Of course, the real problem 95% of the time is really around the device not the technology the device uses. There is a misalignment of incentives on who can work on the device, whether standard parts are used, and whether the approved parts are the $2 type solution that will cost $800 in on site contractor fees to replace again or the $4 solution which actually stands a chance to being used. Once the device is bought nobody is going to be incented or allowed to do anything but fix it to status quo. It's one reason I had to get out of healthcare IT - it was more often the system getting in the way of what patients and nurses needed to do than the actual technology itself so solving things from a technology perspective felt like running on a treadmill and going nowhere.
But DisplayPort has great optical cables available! I was early in & they were very cheap then (no one trusted them yet), 50m v1.4 for $60. Turns out to be vastly longer than I needed, & got a 20m cable for gaming from the roof. There's even DP 2.1 cables now.
A USB4 with optical transport would be divine.
USB 3.2 Gen 1 though, not USB 4
Consumers are absolutely brutal to cables. Minimum bend radius of copper cables get violated all the time, but copper has a decent chance of continuing to work if bent back. Not so with fiber. Fiber would only work with some heavy armor.
Consumer fiber was actually tried in the past: Optical TOSLINK was briefly popular in the audio world. It was cheap relative to what you’d need for modern high speed fiber, but even that was too much to win out over copper. It faded away.
Even within professionally maintained data centers, direct attach copper is often preferred over fiber interconnects when it’s possible to get away with it.
Fiber is great when called for, but copper wins in practicality when you can get away with it. It’s been proven over and over again across industries.
> Meanwhile, Apple wants $70 a pop for a single, 1m Thunderbolt 4 cable, and that's only been increasing.
You picked the absolute most expensive cable as your benchmark. Look anywhere else and prices are lower and decreasing.
Also, you are wrong about Apple cable prices increasing. They’ve actually dropped the price of their longer cables.
But again, look to the overall market and you’ll see prices going down.
Not everywhere. It's still not as popular as copper but it's not extinct.
EDIT: Looking closer at the wiki (it's been forever since I saw it used), it's when it's being used for surround sound that it compresses it super poorly, for stereo it's just PCM and sounds fine.
EDIT: Looking closer at the wiki (it's been forever since I saw it used), it's when it's being used for surround sound that it compresses it super poorly, for stereo it's just PCM and sounds fine.
You could also use that PCM stream to transmit Dolby Digital or DTS, but that's up to the device, not TOSLINK.
- Pin 1: Ground
- Pin 2: Signal in Phase
- Pin 3: Signal flipped
Two channels over XLR are done in two ways:
- digital using the AES standard and 110 Ohm cables
- analog using two balanced lines and a XLR-5 connector, although this is not an offical standard to avoid confusion with DMX
The only people who would lose out on using TOSLINK was someone listening to a surround SACD (not exactly common).
It was never updated for the higher bitrates on Blu-ray, so that's when it fell out of favor.
Dolbly Digital (ac-3), dts, and 2-channel PCM are fine for what they are. More channels in PCM would be nicer, as would other newer higher bandwidth, lossless codecs, but as a unidirectional signal, it's hard to add support for more stuff. It's not terrible for a standard from 1985 to not support full bitrate audio on blu-ray.
But fiber still isn’t a free lunch. The longest high speed cables already use fiber internally, but they’re expensive because they need extra optics and transceivers inside. Moving the extra fiber hardware into the laptop and client device would make the cables cheaper but make the hardware more expensive. That’s not a trade off that most people would take as most people don’t actually need long cable runs.
The above comment was trying to use Apple premium cables as the reference for being too expensive, but opening Amazon shows plenty of Thunderbolt 4 cables in the $20-$30 range from other vendors. It’s really hard to imagine a scenario where forcing every cable to be a combination of fiber and copper would make things cheaper for us consumers.
I've watched tons of modern fiber and cat6 be abused. My dog dug up and chewed some. 0.5db loss. The copper next to it was a complete loss
The fiber always wins.
As for pricing. Once you get to 10gbps+ its at best a wash.
Transceivers are 10-20 bucks. Cheap rj45 10gbps sfp+ are 2-3x that price. Produce a ton of heat as well. This will only get worse.
25gbps fiber transceivers are now almost as cheap as 10 gbps.
Meanwhie, higher speed copper standards are much more expensive and produce even more heat.
Higher speed fiber is dropping in price.
Higher speed copper is not because nothing drives it anymore.
How did you know how they test for these specs?
You can also find datasheets for industrial cable that specify it for fixed installations and repeated flex applications: https://www.sab-kablo.com/fileadmin/user_upload/pdf/catalog_... (notably this has 5 times the diameter, so it wouldn't pass some standards)
Consumer cables, not just Ethernet, probably do have such specifications when produced in bulk, but the manufacturer that turns reels of 1000 metres of raw cable might not include it in the end manual (just like they usually don't include the frequency response curves in there).
https://en.wikipedia.org/wiki/TOSLINK and https://en.wikipedia.org/wiki/ADAT_Lightpipe are limited to about a megabyte/second, if I’m doing my math right. https://en.wikipedia.org/wiki/MADI#Sampling_frequency gets higher, at around 12 megabytes/second. That still is at least a factor of 100 away from this cable.
I think that’s because it isn’t easy to make a plug that works reliably for a gigabytes per second fiber cable.
used in ai data centers, probably years away from consumer adoption...
https://youtube.com/watch?v=CwZdur1Pi3M
It mostly boils down to the reason others already mentioned: fragility, cost (optical transceivers have only recently become cheap enough to enable the use case of optical cables that behave like copper ones) and the requirement for copper wires anyway in order to carry power in addition to data.
The problem is the ends. Inside each fiber plug is an exposed fiber. Dust is a huge problem if you expect users to toss the cables in their bag, and worse is damage to the exposed ends of the fiber which can get chipped and then then in turn damage the exposed fiber in the device you're plugging into.
It would be cool if instead of those active Corning cables you could just get an active Thunderbolt-to-SMF plug, and then bring your own cables. Then the expensive part (the conversion circuitry and optical transceiver) can be reused for different applications and you just replace the cheap fiber with whatever length you want (or use pre-existing fiber in your home and update the optical transceivers when a new standard comes out and not have to re-wire)
edit: thinking about it more, it would have been a lot cooler if instead of thunderbolt we just got a better Ethernet. Then we could use any medium we wanted to.
It is an amazing display and I love it, but I would never buy one for myself. It is obviously fine for programming, but for me it really stands out as something for consuming entertainment, even though I only get 4K content. It is capable of, I think, 7K with the right computer and has 10 bit color depth. When my Dad first bought it, I used it to play Apple Arcade games on my iPad Pro - that was fairly spectacular.
EDIT: my Dad had a Black Magic video camera that I think had 8K resolution, and so he had a lot of fun with his setup.
I think we’re going to see a “silver tsunami” of robust elderly persons as millennials and Gen Xers age simply because healthy lifestyle activities that had been a part of their lives.
I.e. don’t buy into Acorn Stairlift and Lifealert futures.
You're probably leaving out the issues around teflon, microplastics and antibiotics poisoning all food, air and water, general increased stress and anxiety about the wars, economy, job market, environment, debt and unaffordable rent/housing, the loneliness epidemic plaguing the west, which have already tanked their/our sperm count so we can't be too sure they'll/we'll see much healthier retirements if these keep piling up.
Those with solid careers in tech in developed countries yeah sure, they'll be fine and happy, most likely retired early, house and debt paid off and focused on enjoying their hobbies instead of working the 9-5 grind. The rest, not so much.
The old people working in the streets till they drop in China and Korea do it because they have no wealth to rest on, not because they enjoy doing that kind of work so much.
It's doable to be young and poor, but being old and poor sucks.
On the healthcare front there was the proliferation of lead (in paint, toys, fuel, everything), smog from cars and coal burning, toxic fertilizers, the rise and fall of smoking, the discovery of HIV, Polio outbreaks, things like the Cuyahoga river fire (where rivers were so polluted they literally caught fire every couple decades). The mining town my family lived in would just throw the arsenic and mine tailings into the lakes because they figured it couldn't hurt them there, and that was a common thing to do at that time.
Gen X and Millennials are not the only generations who have faced adversity. It's a rough moment now for sure, but it's not unique. We shouldn't fall into baseless optimism but also don't shouldn't neglect human strength and creativity. We have new problems, and we have new tools.
Sure, not stealing his thunder, but that's how selection bias works. Not everyone got to live to 101 despite maybe even living healthier lives. I know people in their 40's who already died of cancer. Life can always throw you a curb ball.
>Gen X and Millennials are not the only generations who have faced adversity.
Fair point.
My point really was that second one.
As I said, it's a rough time right now, we're going through a lot. But we passed environmental reforms before, we removed lead from gas, we invented vaccines, we set standards for chemicals, we've cured a few people of HIV, there is good to find out there.
Thank you for this comment, it helps to contextualize two moods that I have, as one who has struggled with depression (not currently, but off and on):
When I’m in a low mood it’s easy to see and dwell on the new problems and discount the efficacy of the new tools.
When I’m in good spirits it’s easy to see the new tools and (temporarily) forget about the new problems.
> I.e. don’t buy into Acorn Stairlift and Lifealert futures.
Trends in obesity–which is a huge driver of poor health in America–don't seem to support this hypothesis. I think the great majority of health and wellness activity in recent years has been concentrated among people at the upper end of the socioeconomic scale, which also drives perception since companies will spend a lot on advertising to attract people with money. Things in this country look very different depending on how far you are from the nearest Whole Foods/Equinox/Soulcycle/Sweetgreen.
It's not a silver bullet anyway, but "become generic" is doing some extremely heavy lifting.
Through that lens it seems like a useful product.
For everyone else it seems like a pretty amazing monitor if money doesn’t matter. It’s most useful quality is probably being 6k, so you have tons of screen real estate.
However, I've been reading about announcements like this for about five years now with close to zero products actually available to buy.
It doesn't help that Samsung decided that from now on all displays must be curved and ultrawide.
When I look at a high resolution scan of a large format negative on it, it feels like looking at it directly on a light table. It's insane. My only complaint is the local dimming, which shows its limit when you're doing fine white on black linework in a dark room. Hopefully we'll get a pro OLED display of that quality in the next decade which will solve that one issue.
The only other piece of hardware I've spent money on that comes close of giving me the same satisfaction is my Happy Hacking Keyboard, which I've used for over a decade now and I hope I will keep using until I cannot use computers altogether anymore (I have a few spares just in case).
It means a lot for productivity use as well, like smooth cursor movement, smooth browser scrolling, app scrolling etc.
What happens rather is much simpler, the blog post forgot to set the calculator to 10 bit https://linustechtips.com/topic/729232-guide-to-display-cabl... if they did you'd see the data rate required is 38.20gbit/s so the bus is near full. USB C has separate 2.0 wires so unless you have DP 1.4 for DSC you can only use those for USB data, there's no space for anything else.
You can check https://tomverbeure.github.io/video_timings_calculator to see what is possible.
In actuality, the mode where the XDR display consumes 38gbps of uncompressed display bandwidth is an Apple-only mode requiring special Titan Ridge firmware that aggregates 6 lanes of HBR3. Contrary to the article, Alpine Ridge does not support 6k, which specifically is why the iMac Pro doesn't support 6k output. It requiring special firmware is also why this mode only works when directly connected to the Mac.
But yeah, it's annoying that everyone throws bandwidth numbers around without mentioning or even thinking if it's link rate or data rate.
Yes, it's USB4 which added USB packets to the bus, TB3 only had PCIe and DP.
That's rather interesting there, what do you mean by aggregating? Thunderbolt could always carry 40gbps worth of DisplayPort packets and afaik it was not lane bound.
Maybe the spec itself doesn't define a maximum bandwidth allocation for DisplayPort packets, but the DisplayPort stream has to come from somewhere and be output somewhere else, and with one single exception, the actual implementations support two HBR2 streams or one HBR3 stream, with each stream obviously being individually capped to 4 lanes at the physical DP interface.
(AFAIK the special mode combines one 4-lane HBR3 stream with a second 2-lane HBR3 stream)
This is the same reason you see some adapters using DisplayPort alternate mode have a USB 2.0 port only -- in this case, it's DP packets which occupy the four high speed lanes much like Thunderbolt above.
Yes, Titan Ridge must connect via DisplayPort lanes and you are right, it definitely looks like it only takes five lanes, wow. https://support.lenovo.com/us/en/accessories/pd029622-displa... says two 3840*2160@60hz and a 2560 × 1440@60Hz monitor is supported which is 30.71 Gbit/s -- a third 4K would require 37.62. https://www.dell.com/support/manuals/en-us/dell-wd19tb-dock/... explicitly says it's five lanes. https://www.dell.com/support/manuals/en-us/wd22tb4-dock/dell... even TB4 is?? Wow!
Here's a good breakdown: https://www.reddit.com/r/UsbCHardware/comments/mjz2pu/usb4_a...
"Titan Ridge, however, would disconnect the USB 2.0 and USB 3.1 hubs immediately upon entry into TBT3 mode."
"USB4 (and Thunderbolt 4) don't do this for the classic USB 1.1/2.0 wires of D+ and D-. When a hub is operating in advanced USB4 mode, classic USB 1.1/2.0 signals still ride through a normal USB 2.0 hub"
"disabling PCIe also means disabling the way that all Thunderbolt 3 docks get to USB 1.1/2.0/3.2 devices at all"
I don't think Thunderbolt ever uses anything other than 4 lanes per DP connection if the GPU doesn't limit the lane count, because Thunderbolt deserializes DP packets, transmits them over the link and serializes them back on the other end, so it can't negotiate the lane count on the host side.
For the MacBook Pro with M1 Pro it is explicitly mentioned in the tech specs that it supports 6k with 10bpc.
This page claims that even the M1 MacBook Air from 2020 supports 10bpc on the external 6k monitor: https://support.apple.com/en-us/HT210437
But the actual technical spec page for the machine never says it, AFAICS.
https://support.apple.com/kb/SP825?locale=en_US
> Simultaneously supports full native resolution on the built-in display at millions of colors and: One external display with up to 6K resolution at 60Hz
My impression was that Apple implemented Thunderbolt themselves (and got rid of external chips) and that at least the first generation M1 machines lacked the 10bpc feature in the GPU and/or the Thunderbolt part.
The Graphics/Displays page in System Information unfortunately says nothing about colors, only resolution (https://github.com/shurcooL/home/assets/1924134/af4b19a3-b85...).
When looking at a 16-bit PNG of a white to black gradient, I'm not able to visually spot any banding even when zooming in. It's fairly easy to spot steps when looking at a 8-bit PNG version of the same gradient. But the same happens on the built-in display despite it supposedly having only 8-bit color ("support for millions of colors").
You might want to try out SwitchResX and see what it says about the screen. In some menu, there is color depth information about the screen. But I don't know if it is actually accurate and where the application gets this info from.
Thunderbolt 3 uses 64b/66b encoding (unlike display port 1.2 alt mode), so there's more bandwidth left over for non-display protocols.
This leads me to question my USB maths. E.g.: USB 3.2 Gen 1×1 advertised as 5,000 Mbps, but is that pre-encoding or post-encoding?
Is it `5000 Gbps pre-encoding -> 8b/10b > 4000 Gbps` or `6250 Gbps pre-encoding -> 8b/10b > 5000 Gbps`
Same question for USB 3.2 Gen 2×1 which uses 128b/132b (I double checked this time :P!).
USB 3.2 gen 2x1 runs at 10Gbps. After the 128b/132b coding this provides 1212MB/s.
I was just watching a YouTube video describing how to edit HDR videos in DaVinci Resolve, and step #1 was basically: "Get a Mac".
There is simply no monitor equivalent to the Apple Pro Display XDR available from any other vendor, short of the ludicrously expensive Sony mastering monitors that are made to order.
There are no 4K OLED HDR monitors that can hit 1,000 nits, for example. Meanwhile my local electronics store has an entire row of TVs with that spec! There are 6K and 8K monitors... but they don't do HDR, or do it so badly that it's actually making things worse.
Even if there was proper HDR display for PCs, or if I simply forked over $5K for the Apple XDR monitor... it wouldn't work. Not in practice, not for video editing or for photography.
There's something fundamentally broken with the entire Windows and Linux ecosystems that it has been a decade of widespread HDR support everywhere else, but in the PC world it's just crickets chirping and wolves howling in the distance.
Although I have an LG Ergo 4k 32inch at home and I think the 16:9 ratio is just not enough for having 2 windows side by side. You'd only get 1500pixels per window on retina 6K.
I would've liked it to be a bit wider. Or maybe I'd go for a smaller 27 inch, and put my laptop screen as a secondary screen next to it.
Displays shouldn't need allocated bandwidth - they should give the best display quality possible given the available bandwidth.
Nothing moving on the display - no bandwidth used. Just a little animated gif? Just a few kilobits used. Full screen HD video? Gigabits used. Gigabits not available? Frame rate and/or quality drop.
This is the exact behaviour of plugging in hundreds of USB ethernet adaptors. Why should displays be different?
Personally I'd hate to see my display bandwidth drop when I copy files to a flash drive so I'm glad no monitors support that part of your suggestion. Input lag = horrible UX.
Well… if you connect the flash drive to the monitor and not the computer that should be expected. OTOH, I’d love to have faster data rates when my monitor image doesn’t change much (such as when I’m writing code or letting the computer move lots of data between external drives.
Also USB4/thunderbolt already lets you use the same PHY for either a monitor or a flash drive
And now think about what this will mean when you’re actually doing RDP on top of it.
Displays aren’t special. It’s just that they’re moving huge amounts of data hundreds of times per second, so they use a specialized protocol to do so.
OP, the tech exists however contrary to expectations, to have multiple displays attached with a bandwidth constrained connection, the display tends to have all the special bits in it (contrast it with your “please stop having displays be 'special”)
To support no bits moving when image is static, the display must incorporate a framebuffer and once you add franebuffer to the display, it stops being a dumb display. Eg. You can add smarts to it and expose higher level primitives for “display acceleration” and reduce the bandwidth required further… and very quickly the display is just a computer with memory and video accelerator (aka graphics card) connected with a cable.
This is what RDP. Xdisplay and VNC accomplish. The basic complexity is not reduced but moved elsewhere. However the function gained is very useful so they exist and it’s a competitive landscape!
I don't think there are any consumer displays sold today that don't include a framebuffer...
If you're just using normal HDMI or DisplayPort cables there's no bandwidth to share, and since that's the vast majority of display inputs[1], we haven't even had interframe compression until very recently when people started wanting extremely high resolution and high refresh rate displays. The only reason why this seems incongruous now is that we also want to shove this video data through a USB-C cable. USB shares bandwidth across multiple devices based on demand, so why doesn't video over USB? Why don't we just standardize "MPEG over DisplayPort" today so we can shove a video wall of 4K displays over a single cable? Well, a few reasons...
- Computer users expect lossless reproduction. Most lossy codecs only do well on pictures, and absolutely murder text and graphics - which is what most computer users are actually watching. For various technical reasons involving an Nvidia driver bug[2], one of my three displays actually already uses a compressed input - specifically Miracast - and text 'twitches' every few seconds at every GOP[3] boundary. I hate it.
- Lossy compression codecs add latency. This is not merely an artifact of the encoders being slow, some codecs also have 'algorithmic latency' - as in you get no output until you give it a minimum amount of input because the codec needs data to reference so it can remove redundancy.
- Transient loss of USB bandwidth is extremely difficult to debug. Just as an example, Windows can't help me track down the rogue USB device in my setup that unplugs itself at 3PM sharp every day. It just says something about "the last USB device you plugged in", as in, "I can't explain what USB topology is so I'll throw all that bookkeeping work onto you". Now imagine that instead of a minor annoying pop-up, it's a device diverting bandwidth away from my display to itself. The OS developers aren't even going to flash a pop-up for that, they're just going to have the screen glitch out and hope for the best, in that I'll blame the display manufacturer rather than the computer. Neither party wants to have to deal with a tech enthusiast plugging in more displays than their cabling or USB topology can handle and not understanding what limits they hit.
[0] Judging based off the minimum refresh rates in variable refresh rate mode
[1] Desktop systems outright don't support USB-C video altmodes at all, outside of special motherboards or add-in cards for Thunderbolt that give you DisplayPort injection almost by accident. The only monitors that support USB-C video are Apple displays; everyone other monitor company ships DisplayPort or HDMI. This is why Apple users have to carry around adapters and dongles all the time, to the point where Apple actually had to walk back their "single cable future" and put HDMI back in their laptops.
[2] I have three monitors, but only two optical DisplayPort cables to go to my other room. I used to use a DisplayPort MST hub to get my two smaller (1080p) monitors on the same cable, but for some reason my 1080Ti can't read the EDID data off one of the monitors when it's behind an MST hub. I worked around this with custom resolutions - i.e. manually inputting all the display timings - and it worked until a driver update last year. Now, if I ever plug in that second monitor to the hub, the mouse cursor (which I suspect is a hardware overlay) gets stuck on my primary monitor and shows corrupted image data, making my computer unusable.
[3] Group of Pictures - the smallest seekable unit in an intraframe compressed video stream. Keyframes - i.e. frames that do not reference prior frames - are the start of a new GOP and take up significantly more bandwidth as a result.
Eizo has mass-marketed USB-C models.
Based on the D+/- pairs I believe you’re correct. On Titan Ridge and later add in cards USB 2 is expected to be passed through via a motherboard header as the controllers lack a dedicated USB 2 chip.
But if the dedicated USB2 pins were being used, it would just be acting as a USB hub, and the total bandwidth on all ports would be limited to 480 Mbps?
Only USB4 started using those USB2 wires on USB4 connections.
I would like one day a desktop that works under linux, I'm trying gnome from kde currently, still a mess.
Yeah, the OP links to an image of Al Gore in front of 3 displays with the caption
Climate central Gore in his Nashville home office. where he wrote his new book. Mind map software and huge Post-it notes help him order his thoughts [0]
I did some medium-searching but couldn't come up with a name for the mind mapping software Gore used.
Also interesting is how the 3 displays present in aesthetically pleasing way because they are identical (resolution, size, bezels, etc).
Purely a guess, but probably OmniGraffle back then.
For example the Vega MPX cards on the Mac Pro don’t do it, but the 5700 etc cards will give you the added port bandwidth.
> "But why is the 16-inch MacBook Pro able to run USB 3.1 (10Gbps)?"
USB 3.1 Gen 1 is 5 Gbps, not 10 Gbps.
(My Thunderbolt LG Ultrafine 4K also has USB 3.1 Gen 1 ports on it, so I should know...)
Apple's tech support page about their Thunderbolt 4 cable (https://support.apple.com/en-om/HT210997) also states "USB 3.1 Gen 2 data-transfer speeds up to 10Gbps".
I'm a little confused by Apple's machines wouldn't support USB 3.2 Gen 2x2 when they support USB 4 and Thunderbolt. I guess they couldn't figure out how to get faster USB out of their chipset? They list the same limitation on their iMac USB 3 ports (https://support.apple.com/guide/imac/take-a-tour-imac-apd2e7...).
They explicitly say USB 3.1 Gen 1 in the article, and the linked technical document [1]
> "I'm a little confused by Apple's machines wouldn't support USB 3.2 Gen 2x2 when they support USB 4 and Thunderbolt."
Yeah, it's weird, but Apple has never supported Gen 2x2, AFAIK. 2x2 means you have two 10 Gbps channels running in parallel on two sets of pins, but USB 4 does a similar thing to get 40 Gbps and they do support that. Shrug.
[1] https://fabiensanglard.net/xdr/Pro_Display_White_Paper_Feb_2...
Does the monitor have XDR? Does it auto-negotiate extra bandwidth on newer MacBooks?
With DSC, you have at the minimum a fixed amount of bandwidth gain because blanking intervals can always be compressed, and DP is packetized without strict timing limitations. That should be enough to guarantee the additional bandwidth.