Flickering lines on 2nd monitor (DVI)

This appears to be a serious problem, possibly fairly widespread.

=== Me:
- New Al MacBook Pro 15".
- New Mini-DisplayPort to DVI Adapter.
- Viewsonic VP201b LCD, ~4yrs? old.
- DVI cable, apparently shielded & of moderate quality.
- No KVM involved. Notebook -> DP/DVI Adapter -> Monitor DVI-D input.
- Native Resolutions: Notebook: 1440x900. LCD: 1600x1200.

=== Problem:
Lots of snow / flicker on the external display over any black regions. All the time. It looks kind of like I need to adjust my antenna to tune in a distant UHF TV station. Horribly distracting, impossible to do work on.

=== Ineffective Solutions (for me):
- Unplug / replug all cables. (No effect).
- Try with / without AC power connected. (No effect).
- Reverse ends of DVI cable. (No effect).
- Power cycle monitor / notebook. (No effect).
- Move other windows around on screen. (No effect).
- "Sleep Display" via hot corner. (Makes snow worse!).

=== Partial Solutions (for me):
1. When I use the GeForce 9400M ("Better Battery Life"), I get lots of snow.
When I switch to GeForce 9600M ("Higher Performance") (and log out/in again), the snow disappears. I didn't leave it on the 9600M for more than a minute, so it's possible the snow would eventually return. But this is the first change that had any impact on the problem.
2. Additionally, reducing resolution to 1024x768 or below eliminates all snow.
Neither of these solutions are really acceptable.

=== Things I haven't tried that might help:
- Different DVI cable.
- Different monitors (only VGA conveniently available right now).
- Different Mini-DisplayPort -> DVI adapter.
- Mini-DisplayPort -> VGA adapter.
- Other DVI sources for this monitor (MBP is first DVI source).

=== Related Issues:
http://discussions.apple.com/thread.jspa?threadID=1778280
http://discussions.apple.com/thread.jspa?threadID=1760586
http://discussions.apple.com/thread.jspa?messageID=8338326

=== You should:
Call Apple Care immediately and report this issue. It's possible that a driver update might correct this. Hopefully it's not a widespread hardware issue. Apple needs to know the extent of the problem! Post here if you're seeing this too.

I am having the same problem with snow and static lines all over the screen of my 2nd monitor. Reconnecting my Mini DisplayPort/DVI connector always fixes it though.

Me: MacBook Pro (Late 08) 2.4ghz GeForce 9400M/9600M GT 256mb VRAM

Oh I forgot to mention that my 2nd monitor is an Apple Cinema 20" (Aluminum casing, stand)

Hav same issue on my Dell and my Samsung will not even sync.

I am grumpy calling apple now.

It seems that different "solutions" work for different people differently.

For example many people report that disconnecting/reconnecting DVI cables temporarily fixes the problem for them. For me, it has no effect.

And for me, changing to "Higher Performance" essentially eliminates the problem (with the added benefit of being able to cook an egg on my left speaker). For other people, this has no or only minor impact.

In summary, there seems to be a shared problem here, with a few workarounds that might help various people. Of course none of these should be necessary on a brand new supposedly QAd $2k machine. Let's hope Apple comes up with a real answer soon.

Remember, if you're having these problems, call Apple Care and let them know so they can start to see the extent of this!

I have the same problem.

Brand new aluminium MacBook connected to 20" Cinema Display.

Reconnecting the cable always solves the problem for me - but that's a major pain in the *** since it switches to the internal display and rearranges all my windows, palettes etc. etc.

Please solve this Apple!

I have the same problem with the same hardware.

Has ANYBODY with the flickering / snow on external monitor problem exchanged their MBP and found the problem goes away? This would be a great data point to indicate faulty hardware. Similar question for the MiniDP->DVI adapter.

I'm experiencing this exact problem on my 2008 MacBook with a 20" Apple Cinema Display, so it's not just limited to the MacBook Pro.

If the display is allowed to turn itself off, the external monitor will flicker with various colored lines if it comes back at all. Unplugging and reconnecting the monitor fixes the issue.

Complete reinstall had no effect. The monitor works fine on my C2D Mac mini.

The same flickering behavior is happening for me too with a Dell 1905FP monitor connected via DVI. Upon plugging it into my MacBook Pro with the Mini-DVI adapter, the screen lights up and the desktop background appears but there is so much static/flickering/distortions that it is unusable. If I change the screen resolution down from the optimal 1280x1024 down to 800x600, the distortions almost completely disappear; but obviously that will not do! I am calling Apple Support now regarding this.

My new MBP 2.53 using 9600MGT would awake from monitor sleep and (three times) the screen on my external monitor would be completely distorted - snowy and flickering. It was completely unusable. I had already contacted the store regarding a bluetooth issue but I was really close to the 15 day exchange/refund time and the store manager agreed to give me some extra time to sort out the bluetooth issue. THEN, this external screen popped up and I said 'that's it'!! I called the store manager, (who always wants to see things replicated in the store), that I was having this external monitor issue and that it has occurred three times so far and I was unable to replicate the anomaly at will. I told him that I wasn't going to spend a day in the store trying to produce this flickering issue and that either he could exchange the unit for another or give me my money back. I even said that would eat the 10% restocking charge. At that point he said he would exchange the unit. He gets two gold stars!!

So.... the new unit is trouble free. No issues whatsoever. No external flickering screen, no bluetooth issues and wireless works like a charm. I would also like to point out that my external monitor is a 2 year old CD but that really shouldn't matter. My computer is used as a desk top most of the time and it never goes to sleep, nor do the hard drives ever power down. The first computer was setup the same way. The only piece of hardware that I had set to sleep was the monitor. I felt, and still feel that the flickering is a hardware issue and I didn't want to deal with that. I was fortunate to have had that anomaly during my exchange period.

I resolved my issue. It turns out that the DVI cable was becoming disconnected from the back of the monitor. After I pushed it on further, everything appeared properly.

My second MacBook pro has now exhibited the same flickering issue when waking from sleep. I am now very convinced that this is a graphics card issue which doesn't have a fix yet. Only Nvidia can fix this issue and that takes time and also means that computers in the field with this problem will have to have logic boards replaced which takes more time. Not everyone uses portable computers as desktop computers so those users will not be affected by this issue. This is really disappointing!!

I agree. It is very disappointing. I can't believe there wasn't better QA on this before release. It looks like the new MBPs 9400 just doesn't know how to play nice with a good portion of DVI monitors out there.

I'm considering leaving my 9600 enabled full time until this problem is resolved. The heat is really annoying, though. I worry about the longevity of my notebook as a result.

Another solution (for me at least) is to get the DP->VGA adapter and use that on my LCD. I wonder if the issues would disappear then? Still, not a satisfactory solution (lower quality), and not relevant for other ppl without VGA in.

It would be really great to hear from Apple/NVIDIA with their plans are for addressing this issue! I hope this isn't a ploy to get everyone to buy Apple's new $900 display. That would be really shady.

Am pretty sure my issues are the same as everyone here but just to clarify, I videoed a few seconds worth of my screen playing up and posted it on youtube...

http://uk.youtube.com/watch?v=AgbN1NlWsLA

Am waiting a call back from Apple for an email address so I can then send them the link too.