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

[avro707]

My dust-bin is doing this same flickering too. I'm suspecting a cable issue (mini display port to display port) because it didn't do this with HDMI. I've got a Dell 27" 4K screen.

This also didn't happen with a standard Apple Cinema Display connected.

All the GPU temps are cool.

 

[Mead]

Apple Pro Support kindly (after a few months!) took my Mac Pro back and installed new graphics cards.
Had it back and sadly it still has the white line issue.

Not tried it with 12.0.1 (21A559) yet.

My case with Apple has now been closed as they can not suggest any further actions. I too am tied, but have to thank the chaps at Apple Support in Ireland for doing all they can.

Im going to keep with HD displays until its time to move to Apple silicon.

 

[Riviera122]

Two years on - any further updates or solutions on how to fix this? Using my 6,1 with an LG Ultrafine 4K (Mac version). Still having white line flickering in Monterey. It doesn't seem to happen on every model - I've bought a few other Mac Pros to test out and neither of them had the issue. Tried just about everything except a dummy HDMI connector.

 

[chkwong]

I use Dummy hdmi to solve the problem

 

[h9826790]

Two years on - any further updates or solutions on how to fix this? Using my 6,1 with an LG Ultrafine 4K (Mac version). Still having white line flickering in Monterey. It doesn't seem to happen on every model - I've bought a few other Mac Pros to test out and neither of them had the issue. Tried just about everything except a dummy HDMI connector.

May I know if the screen flicker or not when you playing videos?

I don't have 6,1, but from my experiences of the HD7950 (same family GPU as the D700). This flickering issue is the macOS driver issue. This problem exist only in OSX / macOS since OSX 10.8.3, and Apple never fix it (I reported many times, they replied, but never fix it).

In my own experience, flickering only happen during VRAM clock speed changes. This is why the dummy works. When multiple monitors connected (including dummy). AMD GPU will keep the VRAM at high clock speed. No VRAM clock speed changes means no flickering.

For HD7950, we can simply flash the card to eliminate the flickering issue

Screen Flickering with Sapphire 7950 Mac Edition

No question that you'll see a real improvement over a 5770. Couldn't scrape up the cash for an actual Mac Edition, so I'm running a flashed MSI Twin Frozr 7950 in my 4,1 that replaced the 4870. 10.9 has been a solid upgrade for performance. The little flickering I saw in 10.8.4/.5 are gone in...

forums.macrumors.com

However, I don't think anyone should flash a D700 on the 6,1. Therefore, the same method won't work.

However, since dummy can work, which means, most likely it's the same issue as the HD7950 on cMP. If this is true, then all we need to do is to find out "how to keep the VRAM at high clock speed".

Since playing videos will also put some demand to the GPU, therefore, it may work. If you never see any flickering when watch videos. Then may be you can simply use dynamic wallpaper (e.g. via this app) to keep the desktop play videos as wallpaper.

This of course will increase idle power consumption (same as using dummy). But if it works, then can be a simple work around.

P.S. I am not sure if keep the player open and loop a video at the background can provide the same effect, but worth to try (if playing videos in the foreground can work around the issue).

 

[stevebatter]

I also had a flickering problem with my Mac Pro 6,1 when I started to use a 4K display, the solution for me was to either run two displays (one also using HDMI) or to use a dummy HDMI plug at the same time, as chkwong above has suggested.

I can't remember why this works but I got the solution from the Mac Rumors forum somewhere so you might be able to find it. Since I plugged in a second display, I've never had the problem again.

 

[Riviera122]

May I know if the screen flicker or not when you playing videos?

Thanks for your detailed post. Yes it happens both when playing and not playing videos. But with the amount of auto-play on everything these days, who knows. If it's a driver issue, it's confusing why I didn't get any flickering at all on another Mac Pro 6,1 I tried. I used it pretty much constantly, exact same setup, and not one flicker. I'll try setting a dynamic wallpaper and see if it changes anything.

 

[h9826790]

Thanks for your detailed post. Yes it happens both when playing and not playing videos. But with the amount of auto-play on everything these days, who knows. If it's a driver issue, it's confusing why I didn't get any flickering at all on another Mac Pro 6,1 I tried. I used it pretty much constantly, exact same setup, and not one flicker. I'll try setting a dynamic wallpaper and see if it changes anything.

If you have time, you may try to run something like Unigine Valley. Just use the highest preset, which will run in full screen mode. That will keep the GPU VRAM at highest clock speed. And see if can observe any screen flickering. If not, then more likely the same issue (this issue isn't happen on all HD7950 / 7970, but only on some card).

But if you can still see the screen flicker when running such benchmark, then that must be another issue.

 

[frou]

My MP6,1 (D700) would flicker the screen black for a couple of seconds quite often. This would happen with only a DisplayPort monitor connected, and would also happen with the DP Monitor and a HDMI dummy plug connected.

However, getting rid of the HDMI dummy plug and connecting both DP and HDMI to the same monitor seems to have resolved the flickering issue. In macOS, I've set the HDMI to simply mirror the DP, so it's effectively a dummy still (no Extended Desktop).





The theory that when the graphics card/driver determines that it doesn't have enough to do, it switches to its minimum clockrate and that causes some issue with the signal pipeline sounds very plausible to me. Apparently this new configuration keeps it busy enough.