Mid 2015 15-inch MacBook Pro eGPU Master Thread
 
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Mid 2015 15-inch MacBook Pro eGPU Master Thread  

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Matthew Chua Ong
(@matthew_chua_ong)
New Member
Joined: 2 months ago
 

Hey Guys,

I recently bought a CRG9 monitor which has a native resolution of 5120 x 1440. Right now I am plugging in 2 mini DP to DP to run PBP which is treating the CRG9 as 2 monitor running 2560 x 1440 side by side which gives me sort of the 5120 x 1440. Only issue with this is if I want to go full screen mode and other weird stuff with the mac dock and menu bar. Anyways I have a local seller selling a Razer Chrome EGPU. I was wondering if anyone will know that if I got this and connect it to my 2015 macbook pro 15 with a GPU like and AMD 5700XT. Will I be able to output the full resolution of 5120 x 1440 through the eGPU? Any information is appreciated. Thanks!

To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.

.

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joevt
(@joevt)
Noble Member
Joined: 3 years ago
 

@matthew_chua_ong

An eGPU should solve your problem. Search the builds list for 2015 MacBook Pro.

I have a MacBook Pro (Retina, 15-inch, Mid 2015). It has AMD Radeon R9 M370X 2 GB dGPU and Intel Iris Pro 1536 MB iGPU.

I thought that since it has AMD graphics that it should be able to do 5120x1440, but it appears that any resolution wider than 4096 has the same problem that people have with the Mac Pro 2013 AMD D300 or D500 or D700 graphics - the signal outputs as 5120x1440 60Hz but the pixels are slightly garbled (they are doubled horizontally in columns of 4 or 8 pixels and every second column is offset vertically a pixel?).

You can see a photo of the MacPro6,1 5120x1440 problem at
https://gist.github.com/joevt/32e5efffe3459958759fb702579b9529#gistcomment-3250289

I also tried 4128x2322 50Hz, 5120x1440 30Hz, 5120x2880 30Hz, all with the same result.

 

Mac mini (2018), Mac Pro (Early 2008), MacBook Pro (Retina, 15-inch, Mid 2015), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case


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macnexus
(@macnexus)
Active Member
Joined: 3 months ago
 

If I remember well, from my previous tests, I could run my 5K monitor (via 1 x DP 1.2) at 5120 x 2880 @ 46Hz max using the R9 M370X dGPU.... It worked in both HiDPI and non-HiDPI mode and also in both "Million of Colours" and "Billion of Colours" (via SwitchResX).... I find it strange that it does not support 5120 x 1440.. Is this a macOS problem? Does it work in Windows?

Update: Retested and SwitchResX is not allowing me to install custom resolution so I assume it is not supported.

Computer: Mid 2015 MacBook Pro 15" with M370X dGPU
eGPU: R43SG + Sapphire Nitro+ RX 580 8GB


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joevt
(@joevt)
Noble Member
Joined: 3 years ago
 

@macnexus, what 5K display do you have?

I tried El Capitan, High Sierra, and Catalina. They all produced garbled pixels for resolutions > 4096 width from the AMD R9 M370X. Windows would not detect the display (Thunderbolt or AMD driver issue?).

macOS would not accept a resolution > 576 MHz (the max allowed for 10 bpc with DP 1.2) so I could not do 5120x2880 greater than 37 Hz (using CVT-RB timing).

Maybe I need to edit the EDID so my display only accepts 8 bpc? Even if I make the framebuffer use millions of colors, the GPU still outputs as 10 bpc, according to AGDCDiagnose output. This is why SwitchResX needs a wire mode menu for choosing output pixel format (I assume this would be similar to however the Displays control panel sets HDR mode). You can see the wire modes being accepted or rejected with "log show" command in Terminal.app when a display is connected.

 

Mac mini (2018), Mac Pro (Early 2008), MacBook Pro (Retina, 15-inch, Mid 2015), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case


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macnexus
(@macnexus)
Active Member
Joined: 3 months ago
 

@joevt, I have the DIY 5K display (R9A18 driver board) which is detected as Dell UP2715K when used with 2 x DP 1.2, or DP 5K3K when used with 1 x DP1.2. This driver board does not support [email protected] over 1 x DP1.2. I will try to repeat the test if I can. The 5K driver board is sealed in the iMac enclosure so I cannot easily swap the input cables.

 

Computer: Mid 2015 MacBook Pro 15" with M370X dGPU
eGPU: R43SG + Sapphire Nitro+ RX 580 8GB


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Matthew Chua Ong
(@matthew_chua_ong)
New Member
Joined: 2 months ago
 

@joevt

 

Thanks for the example. I get the same result with the images being messed up. At one point in the systems preference I think i saw the 5120 x 1440 resolution, but it had (low resolution) beside it. I will start looking into the eGPU list. Thank you!

 

To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.

.

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macnexus
(@macnexus)
Active Member
Joined: 3 months ago
 
Posted by: @joevt

@macnexus, what 5K display do you have?

I tried El Capitan, High Sierra, and Catalina. They all produced garbled pixels for resolutions > 4096 width from the AMD R9 M370X. Windows would not detect the display (Thunderbolt or AMD driver issue?).

macOS would not accept a resolution > 576 MHz (the max allowed for 10 bpc with DP 1.2) so I could not do 5120x2880 greater than 37 Hz (using CVT-RB timing).

Maybe I need to edit the EDID so my display only accepts 8 bpc? Even if I make the framebuffer use millions of colors, the GPU still outputs as 10 bpc, according to AGDCDiagnose output. This is why SwitchResX needs a wire mode menu for choosing output pixel format (I assume this would be similar to however the Displays control panel sets HDR mode). You can see the wire modes being accepted or rejected with "log show" command in Terminal.app when a display is connected.

 

@joevt, I am not able to add custom resolution via SwitchResX. It just shows as not installed even after reboot. I have the latest version of SwitchResX installed with SIP disabled.

I think it is unlikely that it can support > 4096 pixels width. I will edit my earlier post to avoid confusion and misunderstanding. Apologies for any inconvenience caused. I must have carried out the tests last time on the eGPU rather than the dGPU.

 

Edit: Added screenshot from the test. The test was carried out using 1 x DP1.2. 

Screenshot 2020 08 15 at 16.11.54
Posted by: @matthew_chua_ong

@joevt

 

Thanks for the example. I get the same result with the images being messed up. At one point in the systems preference I think i saw the 5120 x 1440 resolution, but it had (low resolution) beside it. I will start looking into the eGPU list. Thank you!

 

@matthew_chua_ong, I went for the eGPU mainly because the fans on the MBP were constantly running at full speed when connected to any external monitor (even if it is just a Full HD monitor). With the eGPU now driving the 5K display (and setting the MBP to avoid using the dGPU whenever possible), the laptop runs cool and quiet.

Computer: Mid 2015 MacBook Pro 15" with M370X dGPU
eGPU: R43SG + Sapphire Nitro+ RX 580 8GB


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joevt
(@joevt)
Noble Member
Joined: 3 years ago
 

@macnexus, your screenshot shows a scaled resolution. It does not show the custom resolution that you tried. Did you try to make a resolution with less than 576 MHz pixel clock (just reduce vertical scan rate)?

@matthew_chua_ong, "5120 x 1440 (low resolution)" is correct. Low resolution does not mean it has a low amount of pixels - it means it's not a Hi-DPI/retina resolution where things are drawn twice as wide and twice as tall.

Today I will try forcing the AMD R9 M370X to use 8bpc with my display by overriding the EDID.

 

Mac mini (2018), Mac Pro (Early 2008), MacBook Pro (Retina, 15-inch, Mid 2015), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case


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joevt
(@joevt)
Noble Member
Joined: 3 years ago
 

There seems to be no way to force 8 bpc by overriding the EDID for DisplayPort in macOS (overriding the EDID can enable or disable YCbCr though).

I can get 8 bpc from HDMI but that does not solve the problem of > 4096 width from old AMD graphics.

Mac mini (2018), Mac Pro (Early 2008), MacBook Pro (Retina, 15-inch, Mid 2015), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case


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macnexus
(@macnexus)
Active Member
Joined: 3 months ago
 

@joevt, I was not able to create custom resolutions even if it is less than 4096 pixels wide or at 24Hz scan rate. They just show up as not installed even after reboot and SIP disabled. Not sure if this is a problem with SwitchResX (I have version 4.10.1 installed).

I shared the screenshot to make people aware that the screen resolution reported in System Information can be misleading as it clearly shows 5K when it is only 4K.

 

 

Computer: Mid 2015 MacBook Pro 15" with M370X dGPU
eGPU: R43SG + Sapphire Nitro+ RX 580 8GB


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