9400m Nvidia screen flicker after snow leopard install

I have the same problem on late 08 unibody macbook pro. Some here are saying it may be a software related issue. I'm wondering if anyone here try to run windows on boot camp using 9400 and experience the same problem? I wish I had a copy of windows to test it out.

If I remember correctly, the windows drivers don't allow you to choose the 9400M, only the dedicated graphics card. And because these problems only started with Snow Leopard, I hardly doubt the problem will occur in Windows.

I switched to the dedicated card in SL though, and the problem still occurs now and then.

You may be on to something. The problem is definitely resolved by restarting, so it would make sense that the cache has something to do with it. (Unfortunately the problem returns after one or two “sleeps.”) Even if you're right, however, that cures the symptom, not the disease. Apple really should figure out a way to avoid this problem altogether.

I have not been able to duplicate the problem on Boot Camp.

I have a 6 week old Mac Mini with this issue. Worked great until I upgraded to 10.6, after the update my external monitor will flicker continuously after waking up from sleep. Really annoying, I have had to disable sleep mode which is a shame because I loved the way it worked.

Same problem here: no flicker until I installed Snow Leopard.

Same problem, using 2008 MacBook . Same with external display.

Just for the record I am having the same problem. It is very aggravating.
Resetting SMC was of no help.

Same problem, happens on wake from sleep. I can put it to sleep again, and wake it, and the problem typically goes away.

Has Apple acknowledged this problem yet?

I have the same issue.
If the 9400M is enabled the flicker appears at the top and sometimes on the entire screen.
It happens sometimes every half-minute.
I also can see small white stripes which appears briefly and randomly on the screen (best seen on a plain background-wallpaper).

If the 9600m GT is activated, all problems gone.

I hope Apple read this thread and works on this issue.....

Resetting the SMC helped for about 2 days and then the flicker came back. I hope this gets resolved soon!

I am a contributor to this string and want to provide my latest findings, such as they are. First, as mysteriously as the screen flickering appeared when I installed SL is how it has disappeared. I have remained on the 9400 chip set and haven't had so much as a hic cup, although I had severe flickering right after the upgrade.

First, I downloaded and ran Cache Out X to clean out the System, Library, Persistent and User caches. ( http://www.trilateralsystems.com/cacheoutx/) This actually seemed to do the most good as the flickering ceased immediately after I ran this software. It was recommended earlier in this same post, and for me, like that user, it seems to have worked.

One thing I've been doing differently is not putting my laptop to sleep by closing the lid. Instead, I either choose it from the Apple menu or invoke the keyboard shortcut, Option-Command-Eject. I can't swear that those actions are what has changed the behavior of my MBP, but the flickering does seem to have stopped, at least for now. This was a workaround under early versions of Leopard when Sleep didn't work correctly and I thought I'd at least see if it made a difference now.

One other thing I did was to run Applejack with the auto (not AUTO) switch. ( http://applejack.sourceforge.net/#top) My thinking was that I've been using, essentially, the same drive since Tiger. I use Carbon Copy or SuperDuper to upgrade my new computers rather than building them from scratch. My thinking was to let Applejack do a thorough analysis and clean up the catalog, library, etc. of any errors that may have been inadvertently contributing to this problem.

I don't want to represent that these solutions will work for you, but until Apple issues an acknowledgement of the problem, these workarounds may prove helpful, at least to some. Please post any feedback.

Message was edited by: BocaBoy

Since I removed Istat of my mac and that I clean my caches with Cache Out X daily I do not see any more my screen flickering…

The same here. Since Cache Out X, the flicker disappeard. Hopefully maybe not a handware issue....