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6850 and 6870, DisplayPort garbled on reboot

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I am running 3 x 24" 1920x1200 monitors, so I need to use a DisplayPort to run at least one of them. I have 2 Active DisplayPort Adaptors, both certified by ATI. They both work perfectly when I am booted into Windows. When I boot OSX (10.6.8), any Display Port connected monitors come up with a garbled display, until I either unplug/replug the DP cable or switch to another resolution on each affected monitor then switch back to the native 1920x1200. It is then fine until I reboot again.

This isn't that bad I suppose but it's quite annoying. Does anyone have any ideas on how I might address this? I have tried a PowerColor 6850 and an XFX 6870, both have the identical behavior with the Display Port connected monitors.

I have attached some images of what I mean by garbled.
 

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3tybagig said:
I did a lot of work optimizing the 6850 for dual monitors.

Here is all the info.

viewtopic.php?f=15&t=24583

Ty.

Hmm looks like the only thing relevant that I hadn't tried was adding Duckweed to plist. I tried that and it made no difference to my problem.
 
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I don't know if this is of any use... but I'm currently running two Samsung 2443BWs at 1920x1200 and an old 20" Aluminium Cinema Display at 1680x1050 on my 6870

The strange thing is that if I plug either of the Samsungs in via a DP, they display the exact behaviour you describe - but the Cinema Display doesn't - it works perfectly.

At the moment, this isn't a problem, but I'm planning to add another 1920x1200 into the mix, and pass on the Apple display to my partner, so it'll become an issue at that point.
 
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I have a similar but different problem like this.

The symptom is very interesting. When booting or rebooting, I can always see the gray apple screen. But when it is supposed to show the desktop, the display signals are randomly lost. Sometimes I can fix the problem by unplug and replug the cable either at the monitor or the computer side. Sometime I have to reboot. The incidence of successful rebooting is about 60%. However, if I add another HD and a DVD drive, the successful booting rate is less than 20%. It makes wondering whether it is the PSU problems. But the card worked perfectly fine after it boots up.

Any ideas?

My spec is

CPU: i5 2500
Motherboard: GA-Z68X-UD3H
Memory: GSkill 4G x 2
Harddrive: Macsale 120G 6g SSD + Seagate Green
Graphic Card: Gigabyte 6850 OC
Power: Coolmaster 500W
OS: 10.6.8
 
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I had this problem. I was using the Accell adapter that is certified by ATI. I then replaced it with the Apple branded one and the problem went away completely.
 
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akasurreal said:
I am running 3 x 24" 1920x1200 monitors, so I need to use a DisplayPort to run at least one of them. I have 2 Active DisplayPort Adaptors, both certified by ATI. They both work perfectly when I am booted into Windows. When I boot OSX (10.6.8), any Display Port connected monitors come up with a garbled display, until I either unplug/replug the DP cable or switch to another resolution on each affected monitor then switch back to the native 1920x1200. It is then fine until I reboot again.

This isn't that bad I suppose but it's quite annoying. Does anyone have any ideas on how I might address this? I have tried a PowerColor 6850 and an XFX 6870, both have the identical behavior with the Display Port connected monitors.

I have attached some images of what I mean by garbled.

With the 5770 I lose the DP monitor completely (DP to DP input on monitor)in 10.6.8, but it works in 10.6.7. If you guys get this sorted out I will just upgrade to a 68xx card that works.

I will follow your work closely.

Thank You.
 
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HoosierInFL said:
I had this problem. I was using the Accell adapter that is certified by ATI. I then replaced it with the Apple branded one and the problem went away completely.

Interesting, everything I have read says Apple's adaptors are passive (not Active) and therefore do not work on ATI cards. I tried one and it actually does work, BUT, it auto disables my second monitor plugged into HDMI whenever I plug it in, so it does me no good.
 
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straycat264 said:
I don't know if this is of any use... but I'm currently running two Samsung 2443BWs at 1920x1200 and an old 20" Aluminium Cinema Display at 1680x1050 on my 6870

The strange thing is that if I plug either of the Samsungs in via a DP, they display the exact behaviour you describe - but the Cinema Display doesn't - it works perfectly.

At the moment, this isn't a problem, but I'm planning to add another 1920x1200 into the mix, and pass on the Apple display to my partner, so it'll become an issue at that point.

Do you multi-boot Windows and notice this same behavior there? Because on my system, under Windows, everything works as expected, its only OSX. I will try a different monitor though to see if that changes anything.
 
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akasurreal said:
HoosierInFL said:
I had this problem. I was using the Accell adapter that is certified by ATI. I then replaced it with the Apple branded one and the problem went away completely.

Interesting, everything I have read says Apple's adaptors are passive (not Active) and therefore do not work on ATI cards. I tried one and it actually does work, BUT, it auto disables my second monitor plugged into HDMI whenever I plug it in, so it does me no good.

Yes, I have read that you can't do mini display port and HDMI at the same time on these cards. I am running 3 monitors. Two via mini display port and one via hdmi.
 
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