PSA: There are not (yet) any Retina-caliber external displays compatible with Apple's eGPU...

Posted:
in Current Mac Hardware edited June 2017
In yet another likely reason that external graphics card support for Mac will not exit beta until 2018, there are not any external monitors currently on the market, compatible with macOS High Sierra's eGPU feature, that match the pixel density of Apple's own Retina displays.




Sure, there are plenty of 4K and 5K monitors on the market. But Apple's Retina display branding is not actually about resolution -- it's about how many pixels are packed into a square inch.

On the iMac, Apple has defined a Retina display as about 219 pixels per inch on the 21.5-inch 4K model, and about 218 pixels per inch with the 27-inch 5K variant.

Those same resolutions are matched by LG's UltraFine displays, available in a 4K model over USB-C, and a 5K version driven by Thunderbolt 3.


The LG UltraFine series does not accept mini DisplayPort input.


But there's a catch: Neither USB-C nor Thunderbolt 3 will currently work with Apple's eGPU feature in macOS High Sierra, which requires an external monitor. To take advantage of that, you'll need to find a monitor that allows input from mini DisplayPort, or HDMI.

That's because, with limited availability of USB-C and Thunderbolt 3 monitors, no dedicated graphics card (yet) features either port for display output. And there are no HDMI to USB-C or Thunderbolt 3 adapters (only the other way around, with hubs and cables that convert USB-C to HDMI).

Not that you'd want to run it over HDMI anyhow -- that's limited to 30 frames per second.


MSI's USB-C graphics card will add support for one Retina-caliber monitor -- when it ships.


MSI has announced a GeForce GTX 1080 Ti graphics card boasting a USB-C port. That would be compatible with LG's 21.5-inch UltraFine 4K display, but not the Thunderbolt 3 5K model. Also, it's not yet shipping.

And if you survey the landscape of mini DisplayPort and HDMI external monitors, you'll find that there aren't any consumer-focused 4K models that match the pixel density of Apple's Retina displays, nor the LG UltraFine series. Many 4K-resolution monitors are in the 23- and 24-inch range, which reduces the pixel density to under 200, falling short of Apple's Retina display standard.

If you jump up to 5K monitors, there is one non-iMac, non-LG option that is Retina-caliber: Dell's UP2715K 27-inch Ultra HD 5K monitor.

But, yet again, there is a catch: It has been discontinued. You can find it from a few resellers on Amazon, but Dell's own site no longer sells the 27-inch 5K monitor.

Developer Marc Edwards provided a roundup of Retina-caliber monitors last December and came to the same conclusion, finding only Apple's iMacs, LG's UltraFine displays, and the discontinued Dell 5K monitor as "good for Retina." Edwards went a step further and identified monitors considered in "the bad zone," offering pixel counts not at the level of a Retina display, but too far from the 110 pixel-per-inch density ideal for non-Retina displays in macOS.


Via developer Marc Edwards.


"Apple's interface design in macOS is set up so it is comfortable for most people at a density of about 110 pixels per inch for non-Retina, and about 220 pixels per inch for Retina -- text is readable and button targets are easy to hit at a normal viewing distance," Edwards wrote. "Using a display that isn't close to 110PPI or 220PPI means text and interface elements will either be too big, or too small."

It's likely that the lack of options will be addressed over the coming months. In fact, Apple itself announced in April it will be building its own external professional display in 2018, and you can be sure that the Cinema Display successor will feature a Retina display.

And given that LG's own UltraFine 5K monitor stumbled out of the gate with wireless interference, and it doesn't work properly with eGPU support in macOS High Sierra, there is a clear need on the market for alternatives.

In the interim, you won't find an alternative from Apple's own new iMacs, as the company has abandoned the niche Target Display Mode feature that allowed the all-in-one machines to serve as external displays for MacBooks.

All of this helps explain why eGPU support in macOS High Sierra won't officially launch to the public until spring 2018. Until then, users will have to test external graphics cards with limited hardware, and low-resolution displays.
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Comments

  • Reply 1 of 24
    There are 40" 4k displays that run @ ~110dpi, have multiple inputs for several (including legacy) macs and are almost equivalent to 3 x 27" TB displays in portrait mode. Is such a logical next step from the 30" Cinema Display from the Jobs era? Can such can also act like an actual 'Apple TV'? If or when 8k becomes available, could such a size then be retina worthy @ 220 dpi...? iMac Pro II ?
    edited June 2017
  • Reply 2 of 24
    nhughesnhughes Posts: 750editor
    There are 40" 4k displays that run @ ~110dpi, have multiple inputs for several (including legacy) macs and are almost equivalent to 3 x 27" TB displays in portrait mode. Is such a logical next step from the 30" Cinema Display from the Jobs era? Can such can also act like an actual 'Apple TV'? If or when 8k becomes available, could such a size then be retina worthy @ 220 dpi...? iMac Pro II ?
    Considering the Thunderbolt Display was only available in 27 inches, and Apple already has a gorgeous 5K 27-inch Retina display on the iMac, I would not expect a return to 30 inches for Apple's upcoming external monitor. Most likely, Apple will use the same 5K panel found in the iMac, but give the surrounding (presumably chin-less) bezel a more refined appearance than the LG UltraFine 5K. It will be interesting to see if Apple does anything beyond that, like baking in an eGPU to the display, or if they just stick to a barebones panel.
  • Reply 3 of 24
    There's the HP Z27q which is a 5K 27" display available now: https://www.amazon.com/HP-J3G14A8-ABA-LED-Backlit-Monitor/dp/B00VO85RY6


  • Reply 4 of 24
    One of the problems is that Displayport 1.4 is still not available on Macs. This would allow running 5K displays over a single cable. Intel was believed to be to blame for this delay. Once Displayport 1.4 is available then PCIe video cards could use it like they currently do Displayport 1.2a. The new Dell 8K display uses Displayport 1.4, like the Dell 5K display you need to use both ports on the 8K display to a single computer to support driving the massive 8K resolution.

    Due to the massive delay in shipping Displayport 1.4 chipsets from Intel Thunderbolt3 does not support Displayport 1.4 and hence even Thunderbolt3 cannot drive an 8K display.

    Since Displayport can run over Thunderbolt connections it has a cascading impact.

    Also contrary to what the article says, you can do 4K displays at 60fps over HDMI but you need HDMI 2.0 which can be done with some PCIe video cards and with Displayport to HDMI 2.0 adapters. HDMI 2.0 is however not able to do 5K displays, for that you will need HDMI 2.1 which it not yet available. Sadly it is still the case the Apple's support for PCIe video cards is appallingly bad, OS X apparently does not support HDMI 2.0 on the Nvidia GTX 980 card even though it does have a HDMI 2.0 port. It used to be that Apple could argue that a) the Mac Pro was discontinued and b) they never sold these cards themselves, however Apple have admitted they made a mistake with the Mac Pro 2013 and committed to a new 'modular' Mac Pro for 2018 onwards and this therefore is expected to use PCIe video cards. So Apple now have a need to properly support PCIe video cards again, although arguably their drivers have always been inferior even for cards they sold themselves.

    Note: Where the term Displayport is used this equally applies to Mini Displayport.
    nhughesksecxzupscooter63
  • Reply 5 of 24
    aka_JYeageraka_JYeager Posts: 2unconfirmed, member
    Your headline is mistaken.

    Dell has had the UP3218K 8K monitor for sale for some time (Amazon, BHPhoto, etc.) that is 280 ppi. It uses DP connectors which should be available from the vast majority of graphics cards you would put into the eGPU.
  • Reply 6 of 24
    SoliSoli Posts: 9,208member
    Your headline is mistaken.

    Dell has had the UP3218K 8K monitor for sale for some time (Amazon, BHPhoto, etc.) that is 280 ppi. It uses DP connectors which should be available from the vast majority of graphics cards you would put into the eGPU.
    That wil work with Macs?
  • Reply 7 of 24
    nhughesnhughes Posts: 750editor
    supermike said:
    There's the HP Z27q which is a 5K 27" display available now: https://www.amazon.com/HP-J3G14A8-ABA-LED-Backlit-Monitor/dp/B00VO85RY6


    A good find, but it's also discontinued, and can only be purchased used. Why was it (and the Dell model) discontinued? Not enough demand?
  • Reply 8 of 24
    nhughesnhughes Posts: 750editor
    Your headline is mistaken.

    Dell has had the UP3218K 8K monitor for sale for some time (Amazon, BHPhoto, etc.) that is 280 ppi. It uses DP connectors which should be available from the vast majority of graphics cards you would put into the eGPU.
    280ppi, while impressive, is actually out of the range of how macOS is specifically designed. Check the chart included in the story (ideal Retina monitors are ~220ppi, while non-Retina are ~110ppi).

    Also, I cannot find any evidence that the Dell 8K behemoth (which costs $5,000) is at all compatible with macOS or any Mac hardware. At the very least, you would need to occupy two Thunderbolt 3 ports, and convert them to mini DisplayPort, to be able to drive the monitor.
    pscooter63
  • Reply 9 of 24
    SoliSoli Posts: 9,208member
    nhughes said:
     At the very least, you would need to occupy two Thunderbolt 3 ports, and convert them to mini DisplayPort, to be able to drive the monitor.
    I'm guessing you'd have to use two different TB3 controllers, so that would mean one cable on the left side and one on the right of a 15" MBP with USB-C?
  • Reply 10 of 24
    nhughesnhughes Posts: 750editor
    One of the problems is that Displayport 1.4 is still not available on Macs. This would allow running 5K displays over a single cable. Intel was believed to be to blame for this delay. Once Displayport 1.4 is available then PCIe video cards could use it like they currently do Displayport 1.2a. The new Dell 8K display uses Displayport 1.4, like the Dell 5K display you need to use both ports on the 8K display to a single computer to support driving the massive 8K resolution.

    Due to the massive delay in shipping Displayport 1.4 chipsets from Intel Thunderbolt3 does not support Displayport 1.4 and hence even Thunderbolt3 cannot drive an 8K display.

    Since Displayport can run over Thunderbolt connections it has a cascading impact.

    Also contrary to what the article says, you can do 4K displays at 60fps over HDMI but you need HDMI 2.0 which can be done with some PCIe video cards and with Displayport to HDMI 2.0 adapters. HDMI 2.0 is however not able to do 5K displays, for that you will need HDMI 2.1 which it not yet available. Sadly it is still the case the Apple's support for PCIe video cards is appallingly bad, OS X apparently does not support HDMI 2.0 on the Nvidia GTX 980 card even though it does have a HDMI 2.0 port. It used to be that Apple could argue that a) the Mac Pro was discontinued and b) they never sold these cards themselves, however Apple have admitted they made a mistake with the Mac Pro 2013 and committed to a new 'modular' Mac Pro for 2018 onwards and this therefore is expected to use PCIe video cards. So Apple now have a need to properly support PCIe video cards again, although arguably their drivers have always been inferior even for cards they sold themselves.

    Note: Where the term Displayport is used this equally applies to Mini Displayport.
    Lots of good information here, thank you for posting. I tried to keep this as simple as possible, because I think most casual readers would be surprised to learn that they cannot use the Apple-endorsed LG UltraFine monitors with the new eGPU capabilities of High Sierra. Still, I suspect this will be resolved in due time, and hopefully we get DisplayPort 1.4 on Macs before Spring of 2018.
  • Reply 11 of 24
    nhughesnhughes Posts: 750editor

    Soli said:
    nhughes said:
     At the very least, you would need to occupy two Thunderbolt 3 ports, and convert them to mini DisplayPort, to be able to drive the monitor.
    I'm guessing you'd have to use two different TB3 controllers, so that would mean one cable on the left side and one on the right of a 15" MBP with USB-C?
    If someone out there has paid for this monitor and can test it, we would love to hear about it. I cannot find any evidence that multiple-signal transport is supported in macOS, so I am skeptical that it would work.
  • Reply 12 of 24
    johnbearjohnbear Posts: 87member
    well, if the third party monitors are not compatible according with Mac Sierra and apple low priority for such compatibility, go to http://www.madrau.com and download their tool to make things compatible;) 
    compatibility in mac os x has come a long way, I remember a year or two ago I wasnt able to run my MacBook pro 2013 in retina mode on my 4k TV but now works nicely. If it doesn't for you and your 4-5k monitor just use the SwitchResX. 

    "But Apple's Retina display branding is not actually about resolution" hahaha, if that's the case get a small monitor with the highest resolution possible if you want small pixels. 
    And do a little more research before writing this article!
  • Reply 13 of 24
    One of the problems is that Displayport 1.4 is still not available on Macs. This would allow running 5K displays over a single cable. Intel was believed to be to blame for this delay. Once Displayport 1.4 is available then PCIe video cards could use it like they currently do Displayport 1.2a. The new Dell 8K display uses Displayport 1.4, like the Dell 5K display you need to use both ports on the 8K display to a single computer to support driving the massive 8K resolution.

    Due to the massive delay in shipping Displayport 1.4 chipsets from Intel Thunderbolt3 does not support Displayport 1.4 and hence even Thunderbolt3 cannot drive an 8K display. [...]
    Thunderbolt 3 has enough bandwidth to handle two full DP 1.2 streams. So the LG 5K "ultra fine" (retina) only needs a single Thunderbolt 3 cable even though the display is wired internally as two displays.

    The Dell 8K doesn't support DSC (display stream compression) so it needs both DP 1.4 cables to run at 60 fps. If it did support DSC, then it could use a single DP 1.4 cable.

    You are right that Thunderbolt 3 does not yet support DP 1.4, even though it has enough bandwidth to do so. Intel will likely support it by 2018, in time for the Mac Pro. Maximum DP 1.4 resolutions and frame rates:

    DP 1.4 w/o DSC: 8K @ 30 Hz; 5K @ 60 Hz
    DP 1.4 w/ DSC: 8K @ 60 Hz; 5K @ 120 Hz
  • Reply 14 of 24
    nhughes said:

    Soli said:
    nhughes said:
     At the very least, you would need to occupy two Thunderbolt 3 ports, and convert them to mini DisplayPort, to be able to drive the monitor.
    I'm guessing you'd have to use two different TB3 controllers, so that would mean one cable on the left side and one on the right of a 15" MBP with USB-C?
    If someone out there has paid for this monitor and can test it, we would love to hear about it. I cannot find any evidence that multiple-signal transport is supported in macOS, so I am skeptical that it would work.
    My understanding is that the current Mac Pro can in theory drive the Dell UP3218K at 30 Hz using two DP 1.2 cables. But 60 Hz is out of reach -- DP 1.4 is needed for that.

    Similar to the current Mac Pro driving the old Dell UP2715K, which required dual DP 1.2 cables. So there is support for it in macOS?
  • Reply 15 of 24
    nhughesnhughes Posts: 750editor
    johnbear said:
    well, if the third party monitors are not compatible according with Mac Sierra and apple low priority for such compatibility, go to http://www.madrau.com and download their tool to make things compatible;) 
    compatibility in mac os x has come a long way, I remember a year or two ago I wasnt able to run my MacBook pro 2013 in retina mode on my 4k TV but now works nicely. If it doesn't for you and your 4-5k monitor just use the SwitchResX. 

    "But Apple's Retina display branding is not actually about resolution" hahaha, if that's the case get a small monitor with the highest resolution possible if you want small pixels. 
    And do a little more research before writing this article!
    Current small and medium monitors with the highest resolution possible, and that work with High Sierra eGPU, do not fall under the definition of Apple's Retina display. That's the entire point of the article, and the research behind it.
  • Reply 16 of 24
    Mike WuertheleMike Wuerthele Posts: 4,805administrator
    nhughes said:

    Soli said:
    nhughes said:
     At the very least, you would need to occupy two Thunderbolt 3 ports, and convert them to mini DisplayPort, to be able to drive the monitor.
    I'm guessing you'd have to use two different TB3 controllers, so that would mean one cable on the left side and one on the right of a 15" MBP with USB-C?
    If someone out there has paid for this monitor and can test it, we would love to hear about it. I cannot find any evidence that multiple-signal transport is supported in macOS, so I am skeptical that it would work.
    My understanding is that the current Mac Pro can in theory drive the Dell UP3218K at 30 Hz using two DP 1.2 cables. But 60 Hz is out of reach -- DP 1.4 is needed for that.

    Similar to the current Mac Pro driving the old Dell UP2715K, which required dual DP 1.2 cables. So there is support for it in macOS?
    There is not. I just spoke to high-end Dell enterprise support, somebody I've known for about a decade -- who owns a 2016 MacBook Pro.

    Here's the direct quote, when asked if the 8K display supports MacOS:

    “No, and only on very, very few video cards for Windows 10 creator’s edition”

    And how does he know? Because he tried.
    edited June 2017 nhughesSoli
  • Reply 17 of 24
    ksecksec Posts: 1,566member
    One of the problems is that Displayport 1.4 is still not available on Macs. This would allow running 5K displays over a single cable. Intel was believed to be to blame for this delay. Once Displayport 1.4 is available then PCIe video cards could use it like they currently do Displayport 1.2a. The new Dell 8K display uses Displayport 1.4, like the Dell 5K display you need to use both ports on the 8K display to a single computer to support driving the massive 8K resolution.

    Due to the massive delay in shipping Displayport 1.4 chipsets from Intel Thunderbolt 3 does not support Displayport 1.4 and hence even Thunderbolt3 cannot drive an 8K display.

    Since Displayport can run over Thunderbolt connections it has a cascading impact.

    Also contrary to what the article says, you can do 4K displays at 60fps over HDMI but you need HDMI 2.0 which can be done with some PCIe video cards and with Displayport to HDMI 2.0 adapters. HDMI 2.0 is however not able to do 5K displays, for that you will need HDMI 2.1 which it not yet available. Sadly it is still the case the Apple's support for PCIe video cards is appallingly bad, OS X apparently does not support HDMI 2.0 on the Nvidia GTX 980 card even though it does have a HDMI 2.0 port. It used to be that Apple could argue that a) the Mac Pro was discontinued and b) they never sold these cards themselves, however Apple have admitted they made a mistake with the Mac Pro 2013 and committed to a new 'modular' Mac Pro for 2018 onwards and this therefore is expected to use PCIe video cards. So Apple now have a need to properly support PCIe video cards again, although arguably their drivers have always been inferior even for cards they sold themselves.

    Note: Where the term Displayport is used this equally applies to Mini Displayport.
    Basically this, Blame Intel. But may be due to Intel's reluctance to add or improve is what we got( I believe ) Apple to be involved and now TB will soon be an Open Standard. Hence the support coming in 2018.

    Unfortunately the TB3 is barely able to push the 5K Display. To get the crisp and smooth 120fps screen on iPad Pro on Mac we may need to wait yet another year til 2019.   
  • Reply 18 of 24
    aka_JYeageraka_JYeager Posts: 2unconfirmed, member
    nhughes said:
    Your headline is mistaken.

    Dell has had the UP3218K 8K monitor for sale for some time (Amazon, BHPhoto, etc.) that is 280 ppi. It uses DP connectors which should be available from the vast majority of graphics cards you would put into the eGPU.
    280ppi, while impressive, is actually out of the range of how macOS is specifically designed. Check the chart included in the story (ideal Retina monitors are ~220ppi, while non-Retina are ~110ppi).

    Also, I cannot find any evidence that the Dell 8K behemoth (which costs $5,000) is at all compatible with macOS or any Mac hardware. At the very least, you would need to occupy two Thunderbolt 3 ports, and convert them to mini DisplayPort, to be able to drive the monitor.
    Hmm, i will try to reply to several questions at once.

    Tenthousandthings has covered a lot of the ground work. Mostly you would be looking at the current and slightly older AMD and NVidia offerings which use DP 1.4  and HDMI 2.0b though the cards use full DP sized connectors, so using a mini-DP adaptor is not necessary. If you look at the Dell user manual for this monitor, it uses the AMD RX 480 as an example for setting things up -- a card which easily fits in a Mac Pro, or an eGPU (or if you wish, a hackintosh). The RX 580 is the 480's replacement. These cards have been gaining support since around 10.12.2 or so and is almost completely good to go in 10.12.6, even more so in 10.13.

    There is some speculation that Apple does offer limited support for MST monitors via the AMD graphics kexts, but you have to muck around in the kexts to enable that support. Turn on occurrences of CFG_USE_AGDC to true in the kext that supports your card. This seems to be turned off by default.
  • Reply 19 of 24
    My understanding is that the current Mac Pro can in theory drive the Dell UP3218K at 30 Hz using two DP 1.2 cables. But 60 Hz is out of reach -- DP 1.4 is needed for that.

    Similar to the current Mac Pro driving the old Dell UP2715K, which required dual DP 1.2 cables. So there is support for it in macOS?
    There is not. I just spoke to high-end Dell enterprise support, somebody I've known for about a decade -- who owns a 2016 MacBook Pro.

    Here's the direct quote, when asked if the 8K display supports MacOS:

    “No, and only on very, very few video cards for Windows 10 creator’s edition”

    And how does he know? Because he tried.
    Just to be clear, I meant the "current" (2013) Mac Pro, not any MacBook Pro. The old 5K Dell worked via dual DP 1.2 cables. Was that not "multiple-signal transport?" In addition, the LG 5K Ultrafine also uses dual DP 1.2 streams, via one Thunderbolt 3 cable. So, unless I'm deeply confused (entirely possible), there is support.

    Maybe there is a limitation of the current Mac Pro graphics that prevents using the new 8K Dell. Your contact/friend's comment suggests as much, but I don't think lack of macOS support for multiple-signal transport is the problem. In theory, dual DP 1.2 streams can drive an 8K display at 30 Hz. I don't know why you'd buy a $5000 display only to run it at half its frame rate, but there you go.
    edited June 2017
  • Reply 20 of 24
    nhughes said:
    There are 40" 4k displays that run @ ~110dpi, have multiple inputs for several (including legacy) macs and are almost equivalent to 3 x 27" TB displays in portrait mode. Is such a logical next step from the 30" Cinema Display from the Jobs era? Can such can also act like an actual 'Apple TV'? If or when 8k becomes available, could such a size then be retina worthy @ 220 dpi...? iMac Pro II ?
    Considering the Thunderbolt Display was only available in 27 inches, and Apple already has a gorgeous 5K 27-inch Retina display on the iMac, I would not expect a return to 30 inches for Apple's upcoming external monitor. Most likely, Apple will use the same 5K panel found in the iMac, but give the surrounding (presumably chin-less) bezel a more refined appearance than the LG UltraFine 5K. It will be interesting to see if Apple does anything beyond that, like baking in an eGPU to the display, or if they just stick to a barebones panel.
    No doubt 27" 5k retina is gorgeous, and no return suggested - a next step perhaps, towards 40" @ 8k when the trickle down arrives...

    In terms of 'retina caliber', such may not be a mandatory one solution fits all as suggested, and linked prior:
    diglloyd.com/blog/2017/20170107_1234-evaluating-images-pixel-density.html
    diglloyd.com/blog/2017/20170108_2112-choosing-pro-display.html

    Clearly for some not all pro work is better @ 220 dpi vs 110, aside from Apple offerings, and if an eGPU can boost performance offering a 'mobile desktop' option @ 4k,
    40" @ 110 dpi may be worth consideration for some, and I understand it can also work with macs natively as far back as 2009, replacing upwards of 3 @ 27" display 'real estate'?

    And then there is the prospect of 40" 8k @ 220 dpi... Hmmm...
    edited June 2017
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