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HD7970 in Mac Pro 5.1 (2010 mid)

lcdfans

lcdfans

macrumors newbie
Original poster
Apr 21, 2018
6
0
HI:
I have a HD7970 flashed the efi rom .But I have some problem .
If I connect a 4K monitor to the MINI DP interface alone, the machine will not start.
If I have another DVI 1080 monitor, no boot screen, but wait a minute, the machine will have login OS interface.
If I drop the 4K monitor, and then connect a 1080 of the display to the graphics card of any interface, you can have a normal boot screen,
How do I do? There is no perfect support for 4K graphics card. Thank you!
 
lcdfans said:
HI:
I have a HD7970 flashed the efi rom .But I have some problem .
If I connect a 4K monitor to the MINI DP interface alone, the machine will not start.
If I have another DVI 1080 monitor, no boot screen, but wait a minute, the machine will have login OS interface.
If I drop the 4K monitor, and then connect a 1080 of the display to the graphics card of any interface, you can have a normal boot screen,
How do I do? There is no perfect support for 4K graphics card. Thank you!
Click to expand...

Thanks a known issue. The easiest work around is to keep the 4k screen power OFF until boot to desktop. And let the 1080P screen to do its job.
 
lcdfans said:
There is no way to fix this bug?
Click to expand...

Unless you know how to re-write / mod the 7970 Mac EFI, there is not real fix at this moment.

In fact, unless you really need the Mac EFI on every single boot. It's easier to keep the ROM switch at the PC side. So that all ports and work properly with any monitor. And only switch to the Mac EFI side when you really need it (on that day, you can either set the monitor to DP 1.1, or switch if OFF when booting the Mac).
 
h9826790 said:
Unless you know how to re-write / mod the 7970 Mac EFI, there is not real fix at this moment.

In fact, unless you really need the Mac EFI on every single boot. It's easier to keep the ROM switch at the PC side. So that all ports and work properly with any monitor. And only switch to the Mac EFI side when you really need it (on that day, you can either set the monitor to DP 1.1, or switch if OFF when booting the Mac).
Click to expand...
if I install this HD7970 in my pc . all the ports can be use ,and MINIDP X2 can be 4K 60HZ .
but ,in my Mac Pro , when I use the 4K monitor , it have this bug . if I plug the 4K monitor after the Mac OS login , 4K 60HZ , very good!
 
I have the same card (Gigabybte GVR-7970C). It is flashed and works fine with a Cinema Display. With a Dell UW3818DW monitor it uses Displayport V1.2 and it looks like that is not compatible with EFI. I do not get a Boot display, but it boots fine. Interestingly the BootCamp BIOS screen shows.
If you use APFS it takes up to three minutes to boot from an SSD, so you might just have to wait a while. I have this on a beta partition to monitor the progress on this bug. My main SSD was reverted to HFS+ for 20-40s boot.
 
haralds said:
I have the same card (Gigabybte GVR-7970C). It is flashed and works fine with a Cinema Display. With a Dell UW3818DW monitor it uses Displayport V1.2 and it looks like that is not compatible with EFI. I do not get a Boot display, but it boots fine. Interestingly the BootCamp BIOS screen shows.
If you use APFS it takes up to three minutes to boot from an SSD, so you might just have to wait a while. I have this on a beta partition to monitor the progress on this bug. My main SSD was reverted to HFS+ for 20-40s boot.
Click to expand...
HI:
Thank you for your reply .
can you test it for single 4K screen?
I use 4K screen , it can't boot , unless I add a 1080 Screen Link to mini dp .
thank you !
 
lcdfans said:
HI:
Thank you for your reply .
can you test it for single 4K screen?
I use 4K screen , it can't boot , unless I add a 1080 Screen Link to mini dp .
thank you !
Click to expand...
My screen is not truly 4K, it's 3850x1600 max.
4K is 3840x2160. Most Radeon 7970 can handle up to 4096x2160 using DP 1.2, so 4K should not be an issue. However, you might want to check the details of your specific card. I have seen some 7970 cards listed as only 2560x1600 max on Displayport! DVI and HDMI are limited to that. This might be because the particular card does not implement DP1.2.
 
haralds said:
My screen is not truly 4K, it's 3850x1600 max.
4K is 3840x2160. Most Radeon 7970 can handle up to 4096x2160 using DP 1.2, so 4K should not be an issue. However, you might want to check the details of your specific card. I have seen some 7970 cards listed as only 2560x1600 max on Displayport! DVI and HDMI are limited to that. This might be because the particular card does not implement DP1.2.
Click to expand...
HI:
of course , my MINI dp is 1.2 version . when login the OS X ,the screen is in 3840x2160 ---60HZ .
 
lcdfans said:
if I install this HD7970 in my pc . all the ports can be use ,and MINIDP X2 can be 4K 60HZ .
but ,in my Mac Pro , when I use the 4K monitor , it have this bug . if I plug the 4K monitor after the Mac OS login , 4K 60HZ , very good!
Click to expand...

When you install this card in a PC, the Mac EFI part will be ignored, and the bug will be bypassed.
 
lcdfans said:
So, there is no way to fix this bug?
Click to expand...

Try to reset NVRAM. My Mac Pro 3,1 drives 2 x 3840x2160 (DP) + 1 x 1920x1080 (DVI) with a 7950 card, and it boots normally on the 2K display.

(Another issue is that 10.13.4 will probably not allow you to use 3840x2160 with that card, for some obscure reason. At least that is the case for me.)
 
macdos said:
Try to reset NVRAM. My Mac Pro 3,1 drives 2 x 3840x2160 (DP) + 1 x 1920x1080 (DVI) with a 7950 card, and it boots normally on the 2K display.

(Another issue is that 10.13.4 will probably not allow you to use 3840x2160 with that card, for some obscure reason. At least that is the case for me.)
Click to expand...

2K monitor is not an issue, the issue is the 4K 60Hz (more precise, not necessary 4K, but DP1.2. e.g. 1440P 144Hz DP 1.2 connection will also hang if boot from the HD7950 Mac EFI ROM) connection is not compatible with the 7950's Mac EFI. A PRAM reset won't do anything. It won't change anything inside the monitor. And It can't change anything inside the Mac EFI.
 
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