9400m Nvidia screen flicker after snow leopard install

Same exact problem for me. I call Apple techline today and they have me reset the SMC. It didn't work at all for me. I had the same problem with 10.5 when I was running on the 9400M but not with the 9600M GT. So it's the same problem with 10.6 but it seems to be even worst... At work I'm connected to an external screen and it flicks as well. So it's neither the laptop screen or a connection/cabling problem with the screen.
I tough it could be about the option of adjusting the luminosity of the screen in the control panel to ambient lighting so I set the luminosity of my screen to maximum and deselect this option. The problem still appears. So it has nothing to do about that either.
There must be a problem either with the board or the driver of the 9400M graphics card.
I didn't find anything on nvidia forum about this problem....
About 10.6, I did a clean install...

This is crazy. I had this problem when I first got my late 2008 unibody but only while under the 'better battery life' performance setting (lower graphics card). It took two visits to the apple store, to where they tried to replace the display (didnt' work) and then replaced the logic board. After they replaced the logic board I NEVER AGAIN SAW THE DISPLAY FLICKER UNDER ANY CIRCUMSTANCES! It was fixed! I use my MBP about 4 hours a day and I never once saw it again for over 6 months. The day that I installed Snow Leopard, it is now happening again. What is going on!? I was convinced it was a hardware problem (with the logic board obviously) but now it's happing again with the OS install. Do I go back to the Apple store or what?

Sadly, the problem returned again for me yesterday. I tried to capture it with Jing so I could post it as a bug, but surprisingly, it won't record, even though I can see it happening. That leads me to believe that this isn't a software problem, it has something to do with hardware. Nonetheless, unless it's just a bizarre coincidence, the problem is much worse under Snow Leopard than it was under Leopard.

Shutting down and restarting always seems to fix this problem, and I haven't been able to reproduce it using the 9600.

I have the same problem, which starts to get on my nerve.

I don't believe this is a hardware problem. Or it would be one that every new MBP has, and that is activated with an upgrade to snow leopard.

Obviously, some developer at Apple has seen this thread and because of the many replies with all the same problem, they are working on a fix. It's just not Apple's policy to reply to such posts personally, but rather put the fix in an update and only announce it when it is ready.

I for one, can't wait until the update comes. But hey, in the meantime I can always just switch to the higher performance graphics.

Let's hope that Apple has seen this thread. Wait and see!

I have the same issue. Even since the first beta of 10.6
Hope there will be an update available soon.

Same issue here. Also does anyone else Macbook Pro stutter? Sometimes it freezes and whatever the audio is stutters until I hard restart it.

same problem here mbp 5.1
downgraded to 10.5 no issue
upgraded again to 10.6 issue is here again.

very very annoing

Same problem. MBP unibody. Had this problem in 10.5 when switching to 9400M. With the 10.6 I have the same flickering issue even with the 9600M. Hope in a quick fix.

I'm the original poster of this string. I wanted to report that I've been running the 9600 for the last week and have not experienced any problems, although I see some people say they see the flicker even with this processor.

Regarding the 9400, it sure seems to be related to the way the 9400 NVIDA chipset interacts with Snow Leopard. I, too, had a slight flicker under Leopard, but it never occurred more than once or twice a day. Since I knew I couldn't replicate it predictably for Apple service, I just learned to live with it. Under SL, the problem is really exacerbated to the point where, when it starts, the computer is unusable and I'm forced to shut down and restart to resolve it.

Can anyone narrow down what they're doing when it starts? Are you in a virtual machine, like Parallels or Fusion? Are you using Firefox or Safari? I'm trying to find some commonality that would trigger it, and right now that seems to be a missing piece of information. Since Apple doesn't want to address or acknowledge the problem, it will probably be up to the members of the community to try and narrow this down and see what's causing this widespread issue. It would then be easier to go back to engineering with a method to reliably replicate the problem and get it fixed.

Same problem here... come on apple support, can you at least acknowledge on this thread that you're aware of the issue?

Message was edited by: poiuuiop

Screen flickers (goes black for half a second or so) randomly. Pretty annoying. Glad I'm not the only one with this problem here. Was just fine with Leopard. Flicker started after Snow Leopard clean install (new hard drive too). Apple ought to fix this.

this needs to be fixed asap. seems like loads of other people have this problem. Its pretty annoying.

When I use a software(cache out x for example) to empty my caches I have the impression that the flickering of screen do not appear any more…

Message was edited by: Michael67