Q: MacBook Pro screen blinks

I have noticed that I don't have the problem when I boot my mac in safe mode. Do you guys have the same??

I am having this problem on my refurbished Macbook Pro 2.66Ghz (probably a faulty one returned by previous bloggers!) It's quite frequent at the moment, every 30 seconds or so and it seems to be more frequent after waking from sleep. I have called the Apple care team 3 times and performed the Hardware test, which came back faultless and cleared the Cache and created a new login account. The problem still occurs and I have been asked to look up a local service provider on the website, but the page is unavailable. I think I'll give them one more chance to sort this as I'm wasting a lot of time finding a solution. The Apple Care team needs to pay attention to these blogs, it would save us all a lot of time!

Do me a favor please: boot your mac in safe mode. (holding shift when starting up).

Does the problem occur also in safe mode?
By me it did not so know I know pretty shure it is a software bug and there can be done something about it.

Thanks for the response, but I'm afraid it's still blinking in Safe Mode. I have taken it to Apple but they said if a technician does not witness the fault, I will have to pay for the test, which could take over 7 days. This was even after the person at the store witnessed the blinking. They will also make me pay if it's only a software issue even when it's still under warranty.

The hardware test came back flawless, but the blinking still occurs and more often using the battery saving mode. Shouldn't Apple be doing all this testing? but they seem reluctant to look at it unless the problem can be replicated continuously.

That's too bad! But the whole screen flickers? not just only a part when you're scrolling?

Yes usually the top part of the screen, but sometimes it's the entire screen. I will try the Apple Care team again tomorrow. Thanks again

which videochipset do you have?

Nivdeo 8600? or 9400 & 9600GT?

9400 & 9600GT, and it happens more using the 9400 when on the "Better battery life" option

ah that's weird. I also have the 9400 and 9600GT and I only have the problem when scrolling a stack.
Mine is to be believed a software problem since it only occurs on 10.5.7 and not on 10.5.6.

Did you already perform a pram reset and a smc reset?
And do you have the ability to install 10.5.6? (not downgrade but reinstall with 10.5.6)

If you don't have the flickering on 10.5.6 then maybe it's software related.

Can you post some screenshots or a screencapture of your screen while it flickers?

Yes the Apple Care team got me to perform the resets and the program reoccurred. I am currently running 10.5.6, which is flickering. I will try and capture the flicker for you, but it looks exactly like this one:

http://www.youtube.com/watch?v=xJMuYneBLLE&feature=related

...and mostly occurs at the top of the screen.

I am sorry but I think it's hardware then.
Maybe it is a good idea to update to 10.5.7?
Can you try that? And do all the other updates as well.

Will the upgrade help if it's hardware? I'm not sure how the upgrade will help, especially of you have had problems in 10.5.7. I will ask Apple what they think and get back to you, cheers

Well, in most cases it is good to have the latest software running. And since you have the problem in 10.5.6 anyway you can as easily update to 10.5.7.

And as I said, my problem is different then yours. I only have flickering in the stack when scrolling and not when booted in safe mode. So i'm pretty sure (but not 100%) that it is a software problem with me.

Just an idea:

It may be true that the shared RAM-Memory anything to do with, when you using the 9400??? The 9600m gt uses it's own graphics memory, but the 9400m shares it's graphics ram with the mainmemory ram. Maybe where is an incompartibily to the DDR3-Memory (in my case 4GB of ram)?? Who knows???

Ahh, i noticed anything else:

When i played FlatOut for the Mac on my MBP with the 9400m enabled, the screenflicker appeard mostly every two minutes and when die flicker appears (upper third or the entire screen turned black for a split of a second) the framerate stocks shortly.
With the 9600m gt enabled, the game runs smoothly and everything is fine......

that may be true but I have also this problem when running on the 9600GT....
I have it not as heavy as on the 9400 but still...

please look at this video:
http://www.youtube.com/watch?v=uQBDH9guhEs

This is the problem I have and is different from yours. My whole screen doesn't flicker, only the stack when scrolling in it. (and the safari bookmarks menu for example).