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How to build your own iMac Pro [Successful Build/Extended Guide]

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@kgp do you still have the LG 5K2K?

I bought one today. Works perfectly in Windows.
To be able to access the BIOS, it just be connected to DP2 (on DP1 I have an Apple TB display). With the LG 5K2K in DP1 everything stays black until windows has finished booting.

In macos it boots on a black screen if it's on however. Doesn't matter if it's set to DP version 1.2 or 1.4.
If I turn it on after macos has finished booting, set in DP1.2 the screen shows as 3840x2160 30Hz max.
If set on DP 1.4, can do 3840x2160@60Hz (bit it really looks awful then); it looks best un 2560x1080 mode which is what to be expected.

If I recall correctly, you used a tool to make it recognised at full resolution. Which one was it?

Edit: Okay, found that pressing the option key while looking at the resolution allows me to change res.
Now the issue is that this screen only looks good when using the 2560x1080 resolution. The 5120x2160 looks just too small.

If I connect the screen via TB and use two DP 1.2 (and the screen is set to DP 1.2) then macOS allows to run a native resolution with scaling. The screen when set to looks like 3360x1417 looks very nice and is very usable.

Anyone knows how you could patch so that when connected over DP 1.4 then macOS scaling is available?

Thanks

You need to use SwitchResX under macOS and define a custom 5120 x 2160 , 60 Hz resolution. By this the LG 5K2K perfectly works under macOS with native 5120 x 2160 , 60 Hz or any other resolution via DP1.4 and with DP1.4 enabled in the onscreen display menu. If you use 2560x1080, use the HiDPI profile, which will be available if everything is properly configured on your system, which implements native 5120 x 2160 , 60 Hz resolution but 2560x1080, 60Hz UI resolution.

And yes, I actually replaced my former LG38U99W by the LG 5K2K and I am using the latter every day mainly via DP1.4 as the TB part is still tricky and somewhat buggy.
 
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You need to use SwitchResX under macOS and define a custom 5120 x 2160 , 60 Hz resolution. By this the LG 5K2K perfectly works under macOS with native 5120 x 2160 , 60 Hz or any other resolution via DP1.4 and with DP1.4 enabled in the onscreen display menu. If you use 2560x1080 use the HiDPI profile, which will be available if everything is configured properly on your system, which implements native 5120 x 2160 , 60 Hz resolution but 2560x1080, 60Hz UI resolution.

Any yes, I actually replaced my former LG38U99W by the LG 5K2K and I am suing the latter every day.

I found that I didn't need any software to use the screen at 5120x2160, all I needed to do was press the option key in the screen preferences.
But that's too small, I see 2560x1080 in the list, which is HiDPI, but then that's too big :)

When connected over TB3, it gives more options, can run at full 5120x2160 with 3360x1417 UI. Have you managed to do that using DP 1.4 only?

Thanks
 
@jaminmc have you managed to change the raw-image on the X299-A 1603 with success, if so, do you mind sharing the cap-file? My bios just tells me my CAP file is invalid, altough i am following the guide.
 
@jaminmc have you managed to change the raw-image on the X299-A 1603 with success, if so, do you mind sharing the cap-file? My bios just tells me my CAP file is invalid, altough i am following the guide.

You need to use the new iMac Pro.raw image (recently implemented in and attached to my guide) with reduced file size for modifying your 1603 BIOS with UEFITool. If the firmware modification still does not work, further reduce the size of the image.
 
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Here is mine.
You can't flash it from the bios, as it is missing a checksum or something, and it will fail.. You need to do the Flashback mode. Basically, shut down the computer, put your thumbdrive in the usb port that that is by the biosflash button, and then press the button, and wait for the flashing lite to shut off... Then turn on your computer, and setup the bios to match post 1. (Eccept the Thunderbolt slot is different for the 4th slot on our MB.)
 

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Here is mine.
You can't flash it from the bios, as it is missing a checksum or something, and it will fail.. You need to do the Flashback mode. Basically, shut down the computer, put your thumbdrive in the usb port that that is by the biosflash button, and then press the button, and wait for the flashing lite to shut off... Then turn on your computer, and setup the bios to match post 1. (Eccept the Thunderbolt slot is different for the 4th slot on our MB.)

Oh! Got it , must've missed that part, about the Flashback!

Thanks!
 
Ok calling on @kgp So we are trying to get a beast system working with a GPU external box that connects via one PCI-x16 slot that holds 4 GPUs. This would allow over 6 1080ti`s to run in one system! (4 in box and 2 on mobo). All 6 GPUs work without the Nvidia drivers which is glitchy and laggy, but as soon as we load Nvidia web drivers and boot up it just goes to black screen. With all the GPUs installed it boots all the way until it says waiting for DMOS and then goes to black screen. My guess is once it reaches OSX it doesn't know which GPU is used for main display. We have tried taking out the cable and testing all GPU ports…. still a black screen. This is the same for 10.13.2 - 10.13.6 with Nvidia drivers. It only does this with all the GPUs installed, not when just one 1080ti is installed on the mobo. Is there anyway we can make a custom SSDT to run all the cards? Is this something we can use ioreg to figure out? I thought maybe I need to add all the Nvidia GPU device ID to the config or SSDT files. Please let me know what you think, as if we get this working it opens up a HUGE amount of power for tonymac users! Thank you so much!








7980XE CPU
Asus Prime Deluxe with 1503 BIOS
your latest EFI folder distro
using Lilu and whatever green kexts
 
Ok calling on @kgp So we are trying to get a beast system working with a GPU external box that connects via one PCI-x16 slot that holds 4 GPUs. This would allow over 6 1080ti`s to run in one system! (4 in box and 2 on mobo). All 6 GPUs work without the Nvidia drivers which is glitchy and laggy, but as soon as we load Nvidia web drivers and boot up it just goes to black screen. With all the GPUs installed it boots all the way until it says waiting for DMOS and then goes to black screen. My guess is once it reaches OSX it doesn't know which GPU is used for main display. We have tried taking out the cable and testing all GPU ports…. still a black screen. This is the same for 10.13.2 - 10.13.6 with Nvidia drivers. It only does this with all the GPUs installed, not when just one 1080ti is installed on the mobo. Is there anyway we can make a custom SSDT to run all the cards? Is this something we can use ioreg to figure out? I thought maybe I need to add all the Nvidia GPU device ID to the config or SSDT files. Please let me know what you think, as if we get this working it opens up a HUGE amount of power for tonymac users! Thank you so much!








7980XE CPU
Asus Prime Deluxe with 1503 BIOS
your latest EFI folder distro
using Lilu and whatever green kexts

Did you check NvidiaWeb in config.plist in Section "System Parameters" of Clover Configurator?

If this does not help you can try adapting and implementing a SSDT for each GPU. But I somewhat doubt that this will solve your issue. Anyway worth to try.

Also try to enable/disable "Above 4g decoding"

Good luck,

KGP
 
Did you check NvidiaWeb in config.plist in Section "System Parameters" of Clover Configurator?

If this does not help you can try adapting and implementing a SSDT for each GPU. But I somewhat doubt that this will solve your issue. Anyway worth to try.

Also try to enable/disable "Above 4g decoding"

Good luck,

KGP
Yes we have tried all custom flags such as "NvidiaWeb" Load VBIOS ect. Yes 4G encoding needs to be on to allow memory to the PCI busses. How would I adapt a custom SSDT for those GPUs? Any suggestions? Thanks as always!
 
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