MP 6,1 Mac Pro 6,1 - 12core /D700 flicker issue

R2FX

macrumors regular
Mar 25, 2010
132
85
Came across this thread by chance - my 8 core w D700 has been showing flickering in right side of the screen when using one of the mini DP -> DP cables I have. Upon inspection it turned out that Cable Matters one supports only 2k at 60Hz (something I missed back in 2017) but Amazon basics cable should do 4k at 60Hz. Thing is, the flickering happens with the latter cable and only in Mavericks... Mojave runs just fine!

I also have the Newer headless HDMI but it didn't do anything in Mavericks, flickering remained. My current EFI version is 134... I'm gonna get one proper 4k @ 60Hz mini DP -> DP cables but I'm lost why the flickering occurs on older OS and not on recent one.
 

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daveedjackson

macrumors regular
Original poster
Aug 6, 2009
176
146
London
Came across this thread by chance - my 8 core w D700 has been showing flickering in right side of the screen when using one of the mini DP -> DP cables I have. Upon inspection it turned out that Cable Matters one supports only 2k at 60Hz (something I missed back in 2017) but Amazon basics cable should do 4k at 60Hz. Thing is, the flickering happens with the latter cable and only in Mavericks... Mojave runs just fine!

I also have the Newer headless HDMI but it didn't do anything in Mavericks, flickering remained. My current EFI version is 134... I'm gonna get one proper 4k @ 60Hz mini DP -> DP cables but I'm lost why the flickering occurs on older OS and not on recent one.
This isn’t the same as the flicker I had. This looks like your graphics card is buggered.
 

chkwong

macrumors newbie
Jan 17, 2020
26
5
Came across this thread by chance - my 8 core w D700 has been showing flickering in right side of the screen when using one of the mini DP -> DP cables I have. Upon inspection it turned out that Cable Matters one supports only 2k at 60Hz (something I missed back in 2017) but Amazon basics cable should do 4k at 60Hz. Thing is, the flickering happens with the latter cable and only in Mavericks... Mojave runs just fine!

I also have the Newer headless HDMI but it didn't do anything in Mavericks, flickering remained. My current EFI version is 134... I'm gonna get one proper 4k @ 60Hz mini DP -> DP cables but I'm lost why the flickering occurs on older OS and not on recent one.

hi, it is not the flickering we are discussing
it happens in Mojave or above, at 4K @ 60hz
the right edge has some brief white flickering
I try to attached a photo for your reference
- - Post merged: - -

here is the flickering
- - Post merged: - -

This isn’t the same as the flicker I had. This looks like your graphics card is buggered.

I think the graphics card is not defected. We will get the same if we run Maverick OS X.
I have your "ghost" flickering when I boot into Maverick recovery mode by shift-option-command-R.
it is not a cable problem
 

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Last edited:

daveedjackson

macrumors regular
Original poster
Aug 6, 2009
176
146
London
hi, it is not the flickering we are discussing
it happens in Mojave or above, at 4K @ 60hz
the right edge has some brief white flickering
I try to attached a photo for your reference
- - Post merged: - -

here is the flickering
- - Post merged: - -




I think the graphics card is not defected. We will get the same if we run Maverick OS X.
I have your "ghost" flickering when I boot into Maverick recovery mode by shift-option-command-R.
it is not a cable problem
That's what I had. In a brand new Clean install with nothing installed, nothing attached this flicker appeared out of the door. It sometimes appeared on the login screen too.
 

CC88

macrumors regular
Sep 29, 2010
238
32
That's what I had. In a brand new Clean install with nothing installed, nothing attached this flicker appeared out of the door. It sometimes appeared on the login screen too.
The strange thing is that I don't have it in Mojave 10.14.0. It started from Mojave 10.14.1 and so on. But the hdmi cable solved the issue in my case.
 

R2FX

macrumors regular
Mar 25, 2010
132
85
I think the graphics card is not defected. We will get the same if we run Maverick OS X.
I have your "ghost" flickering when I boot into Maverick recovery mode by shift-option-command-R.
it is not a cable problem
well it doesn't show on HDMI connection (which runs only 30Hz) so I'm puzzled... here's video I took

as for HW / GPU failure I think not, it's just Mavericks that causes this... High Sierra and Mojave run fine on the same cable and resolution (even though I use eGPU 99% of the time to ease the load on D700's)

since it's something 'new' to the initial problem I'll get a new cable and see if it helps
 

chriskuta

macrumors newbie
Jan 16, 2020
11
1
Sydney Australia
hey @chkwong thanks for reporting back and glad it works. Weirdest problem ever. Thanks for your original insight too. I literally just saw mine flickering right now and turned on my second monitor and its now gone. I'm going to grab one of these headless dummies too..
 

chkwong

macrumors newbie
Jan 17, 2020
26
5
hey @chkwong thanks for reporting back and glad it works. Weirdest problem ever. Thanks for your original insight too. I literally just saw mine flickering right now and turned on my second monitor and its now gone. I'm going to grab one of these headless dummies too..

Weird problem
Hope next macos could solve the problem
Look forward to your solution solved by HDMI dummy