Romanesco

macrumors member
Original poster
Jul 8, 2015
88
47
New York City
Hi there,

I'm wondering if I can drive an Apple's Pro Display XDR thru an eGPU (for example Radeon RX 5700 XT, Radeon VII) in a Razer Core X eGPU hooked to a MacBook Pro (for example the 2018, 6-core, 560X). In theory, Thunderbolt 3 supports resolutions up to 8K but I have some confusion in regard to the available ports (4 Thunderbolt on the MacBook Pro and just 1 on the Pro Display XDR).

For those with extended knowledge on these, care to advise?
 

CHA05 R31GN5

Suspended
Oct 31, 2019
165
258
United States
Hi there,

I'm wondering if I can drive an Apple's Pro Display XDR thru an eGPU (for example Radeon RX 5700 XT, Radeon VII) in a Razer Core X eGPU hooked to a MacBook Pro (for example the 2018, 6-core, 560X). In theory, Thunderbolt 3 supports resolutions up to 8K but I have some confusion in regard to the available ports (4 Thunderbolt on the MacBook Pro and just 1 on the Pro Display XDR).

For those with extended knowledge on these, care to advise?
The display doesn't need more than one TB3 port whenever the resolution, scaling, and refresh will be close to saturating the bandwidth for that channel. There are multiple factors which contribute to bandwidth in real-world use than just the marketing department created specifications.
 
Comment

ruslan120

macrumors 65816
Jul 12, 2009
1,384
1,089
You’d need to get one of Apple’s BlackMagic eGPUs since they have a Thunderbolt 3 port. I’m not sure if they officially support the XDR.
 
Comment

Romanesco

macrumors member
Original poster
Jul 8, 2015
88
47
New York City
You’d need to get one of Apple’s BlackMagic eGPUs since they have a Thunderbolt 3 port. I’m not sure if they officially support the XDR.

The Razer Core X has a Thunderbolt 3 port too. If any difference there might be is between the chipset generation (Alpine or Titan Ridge).
 
Comment

ruslan120

macrumors 65816
Jul 12, 2009
1,384
1,089
My understanding is that if you plug in the eGPU into one thunderbolt port on the laptop, and the display on another, the eGPU accelerates applications and doesn’t drive the external display.

I could be wrong on this ?
[automerge]1573699298[/automerge]
(Or does the Razer Core X have two thunderbolt 3 ports?

Laptop <- eGPU <- Display)
 
Comment

RedTheReader

macrumors regular
Nov 18, 2019
204
402
The way owners of the LG 5K have been doing this is taking anything card they like, putting it into an enclosure, having a 2nd smaller enclosure to house Gigabyte's Titan Ridge thunderbolt PCIe expansion card, running a DisplayPort cable from the eGPU into the Thunderbolt card, and then running a Thunderbolt cable to the monitor.

Yes, that's ridiculous to me. So, Laptop -> eGPU -> Thunderbolt card - > monitor.
 
Comment

frou

macrumors 6502a
Mar 14, 2009
944
1,066
You need to be thinking about what ports the actual Radeon graphics card has on it, not about what the Razer enclosure has.
 
Comment

mmomega

macrumors demi-god
Dec 30, 2009
3,800
1,982
DFW, TX
More power to all of you that have the purpose and $ for that monitor. ? I can't even say it's name. I might look at it from the phone case section of the Apple Store.
 
Comment

joevt

macrumors 68040
Jun 21, 2012
3,146
1,437
The Apple Pro Display XDR requires two DisplayPort 1.4 signals over Thunderbolt 3.

The BlackMagic eGPU works with the XDR because it has a Titan Ridge Thunderbolt 3 controller with DisplayPort 1.4 inputs from the GPU connected internally to it. The downstream Thunderbolt 3 port will tunnel the DisplayPort signals to a Thunderbolt Display.

Every other eGPU box only has one Thunderbolt 3 port. If you use a Thunderbolt 3 PCIe enclosure with two Thunderbolt 3 ports to connect a GPU, there is no way for the GPU to output its DisplayPort signals into the Thunderbolt chain. Instead, the DisplayPort signals must come from the GPU inside the computer. The GPU might be limited to DisplayPort 1.2 (Intel instead of AMD graphics) or the Thunderbolt controller of the computer might not be able to transmit DisplayPort 1.4 (Alpine Ridge instead of Titan Ridge).

If you want to connect a Thunderbolt 3 display to an eGPU other than the BlackMagic eGPU, then you need a way to convert two DisplayPort 1.4 outputs from the GPU in the eGPU to Thunderbolt 3. You do that with a GC-TITAN RIDGE Thunderbolt 3 add-in card. A Thunderbolt display connected this way will not allow the computer to see the PCIe devices of the Thunderbolt display (including USB controller which may be required for brightness control, audio, or other features of the display). This method has been known to work with the LG UltraFine 5K display. For brightness control an app that uses DDC/CI over DisplayPort may work.
 
  • Like
Reactions: fzngagan
Comment

RedTheReader

macrumors regular
Nov 18, 2019
204
402
More power to all of you that have the purpose and $ for that monitor. ? I can't even say it's name. I might look at it from the phone case section of the Apple Store.
You might be waiting a while then. I was at the Apple Store on XDR release day (last Tuesday) to buy an LG UltraFine 5K. I knew the XDR was way out of my price range, but I thought I’d at least ask them about student discounts and financing options for it.

Not only did they not know they carried the LG UltraFine 5K, they’d never so much as heard of the Pro Display XDR. Just a friendly reminder of why I straight-up despise the physical Apple Stores.
 
Comment

mmomega

macrumors demi-god
Dec 30, 2009
3,800
1,982
DFW, TX
You might be waiting a while then. I was at the Apple Store on XDR release day (last Tuesday) to buy an LG UltraFine 5K. I knew the XDR was way out of my price range, but I thought I’d at least ask them about student discounts and financing options for it.

Not only did they not know they carried the LG UltraFine 5K, they’d never so much as heard of the Pro Display XDR. Just a friendly reminder of why I straight-up despise the physical Apple Stores.
Very confident you are correct on this.

Also, I am one that when a "thing" whatever it is, is way out of my price range, I understand that and I don't really put a lot of attention on it until it gets closer to reality for me.
Examples like larger real life things for me, my current home, I would not even drive through neighborhoods and essentially day dream and wonder "what if" or "it must be nice". I know it's there, and if I want something bad enough I put my focus in to it, the closer to reality the more research and personal time I put in to it.
My vehicle, when it was introduced... wow, cool, never went to look at one, never had the "want" to drive one because it was out of my reality. Then this year it began getting closer, as the year went on, more and more close and more and more research. I then began going asking questions and looking at them.

I'm just a "different bird" as some say. There are things I could get but unless an expensive thing has a purpose for me, it makes me have the feeling of personally being uncomfortable having it. I don't get things just to get them. Once it clicks for me specifically, it can make more sense to own. ?‍♂️
 
Comment

RedTheReader

macrumors regular
Nov 18, 2019
204
402
… unless an expensive thing has a purpose for me, it makes me have the feeling of personally being uncomfortable having it. I don't get things just to get them. Once it clicks for me specifically, it can make more sense to own. ?‍♂️
I completely understand this and feel the same way. This is my main gripe with the Pro Display XDR. I want a 32” Retina display with the contrast of OLED, but something like that would be in the realm of $2.5K. The Pro Display XDR has a bunch of other features that a lot of people can make use of that double it’s price. I don’t need those features at all, and so I’d feel uncomfortable splurging for it. Splurging for something I can make full use of is much better for me.
 
Comment
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.