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iMac 27" - Screen Flickering

G

Ghosti

macrumors newbie
Original poster
Nov 28, 2009
8
0
Hello all !
27th november 2009 -- FINALY !! My iMac 27" arrived.
I rush to make it run and to update everything, and to get Vista 64 Ultimate running.
FInally installing my games again ( WoW and AION ) and 3 hours later set to play.

1 hour -- Man everything is so nice....
2nd hour -- My mac start to go crazy -- Flickering of the screen
2H15 later -- My Screen turns black for 1 second and comes back...

So is this a heating problem ? Flackering after i played some hours ?
Can i do something ?
Is the first 27" serie not working properly ?

Thanks for your feed backs and help.
 
Ghosti said:
Hello all !
27th november 2009 -- FINALY !! My iMac 27" arrived.
I rush to make it run and to update everything, and to get Vista 64 Ultimate running.
FInally installing my games again ( WoW and AION ) and 3 hours later set to play.

1 hour -- Man everything is so nice....
2nd hour -- My mac start to go crazy -- Flickering of the screen
2H15 later -- My Screen turns black for 1 second and comes back...

So is this a heating problem ? Flackering after i played some hours ?
Can i do something ?
Is the first 27" serie not working properly ?

Thanks for your feed backs and help.
Click to expand...

This is what mine did, you'll need to ship it back for a new one.
 
invisionblue said:
This is what mine did, you'll need to ship it back for a new one.
Click to expand...

You had the same problem ? After playing ? Or in general ?
It's an confirmed bug for some iMac 27" ? Only some or in general ?
The flickering or the overheat ?
How did you manage the shipping back ?
Thanks for all infos ;)

After you recieved new one, the problems came up again ? Are you playing also quiet much on your imac 27" ?
I will try to install aion on Leopard now and too see if the heat is same and if i get also the flickering.
And i will also try smcFanControl t speed up the fans to see if problem will come up also.
 
Ghosti said:
You had the same problem ? After playing ? Or in general ?
It's an confirmed bug for some iMac 27" ? Only some or in general ?
The flickering or the overheat ?
How did you manage the shipping back ?
Thanks for all infos ;)
Click to expand...

My i7 arrived 11/23/09 and was fine for 24 hours however the next day it started flickering. I then called them to report it and they emailed me a fedex label to ship it back free of charge. My replacement it supposed to ship within the next 1-3 days.
 
Aloha everyone,

I returned my first i5 iMac due to a bad USB port, and the replacement iMac also had that flickering issue. After I ran System Update and accepted the installs, at least one of which required a restart, the flickering went away and has not resurfaced.
 
HawaiiMacAddict said:
Aloha everyone,

I returned my first i5 iMac due to a bad USB port, and the replacement iMac also had that flickering issue. After I ran System Update and accepted the installs, at least one of which required a restart, the flickering went away and has not resurfaced.
Click to expand...

i have everything up to date ;()
 
i received my imac27 i7 yesterday. After using for half of the day, i am already experiencing the screen flickering problems a 3" bar going horizontal across the whole screen appearing every once of a while. sometimes in the middle of the screen, sometimes towards the bottom of the screen.
also the whole screen will blink every once a while, cannot duplicate the problems, it just happens.

it feels like a connections problem (like how the video cable isnt connected to the TV tightly, you get that flicker on the tv screen) , but shaking the table where the imac sits cannot duplicate the problem.

my mac is only 1 day old.... i hope i didn't get a defected model
 
PBG4 said:
i received my imac27 i7 yesterday. After using for half of the day, i am already experiencing the screen flickering problems a 3" bar going horizontal across the whole screen appearing every once of a while. sometimes in the middle of the screen, sometimes towards the bottom of the screen.
also the whole screen will blink every once a while, cannot duplicate the problems, it just happens.

it feels like a connections problem (like how the video cable isnt connected to the TV tightly, you get that flicker on the tv screen) , but shaking the table where the imac sits cannot duplicate the problem.

my mac is only 1 day old.... i hope i didn't get a defected model
Click to expand...

As supposed, it's the heat which is too high.
I downloaded a smctempregulator an increased highly the 3 ventiltaors, now it looks like going better. Let's see in the long run.
 
I have a 27inch i5 imac on order.

Is the screen flickering issue a significant issue to worry about?

Do all 27 inch models have this issue?
 
Chucksta said:
I have a 27inch i5 imac on order.

Is the screen flickering issue a significant issue to worry about?

Do all 27 inch models have this issue?
Click to expand...

Yes it is. Some people are apparently not experiencing it, but a large enough number are to have a 47 page thread on the Apple discussion forums and a long one here as well. (I returned my i7 yesterday and rather than swapping, will either wait for confirmation of some kind that this is resolved, or perhaps for the new MBPs in a month or two.)
 
JimAtLaw said:
Yes it is. Some people are apparently not experiencing it, but a large enough number are to have a 47 page thread on the Apple discussion forums and a long one here as well. (I returned my i7 yesterday and rather than swapping, will either wait for confirmation of some kind that this is resolved, or perhaps for the new MBPs in a month or two.)
Click to expand...

Keep in mind that user forums are generally where those with issues go to post about them. It is still a very tiny minority of the i7 owners out there. If it were anything approaching a notable percentage of the machines being sold that were affected you'd be reading about it on tech news sites (and not just reports that folks have been reporting such problems to user forums). Apple would be forced to comment officially or issue a recall.

I'm at 5 days and counting with my i7 and have not experienced any flickering problems yet. I've gotten it pretty hot too.
 
Should I get my iMac replaced? What exactly is causing this problem? Hardware related?

I noticed this on the 3rd day I had my iMac and I turned it off, unplugged it from the wall for about 5 minutes, and then turn it back on. Since then, the problem went away. Another problem, which is minor has surfaced recently though. There is a high pitched noise coming from the screen when it is on and it gets louder when I lower the brightness down to about 30%.
 
California King said:
Should I get my iMac replaced? What exactly is causing this problem? Hardware related?

I noticed this on the 3rd day I had my iMac and I turned it off, unplugged it from the wall for about 5 minutes, and then turn it back on. Since then, the problem went away. Another problem, which is minor has surfaced recently though. There is a high pitched noise coming from the screen when it is on and it gets louder when I lower the brightness down to about 30%.
Click to expand...

I would just go in and have them replace it. Problem solved.
 
Chucksta said:
So is the problem only with 27inch i7 models?

Or is it with all 27 inch models?
Click to expand...

In my opinion it's a general problem.

- Why it doesn't come up for everyone ?
=> Because not everyone uses all the capacity of the iMac, really high and long (>1h) usage of the iMac will bring this problem up.

- Why this problem is for everyone ?
=> iMac have all the same cooling materials

- How can this problem be solved ?
=> An Software update of the fan/cooling controling will make this problem go away.

- What does this update need to do ?
=> Control the fans after the usage (if intense = blow more ; if idleing = go to lowest blowing setting )

- Tested ?
=> Yes. I installed the smc tool for controling the fan speed.
I turned it up for about 55% - 65% of the minimum speed fan and i never go up over 60°C also under full usage for hours. Compared to before when i was at >80°C.

- Why this problem came up ?
=> Because there is no auto regulation of the fan speed / usage.
=> It's blocked to the minimum speed fan and never changes.
 
Ghosti said:
In my opinion it's a general problem.

- Why it doesn't come up for everyone ?
=> Because not everyone uses all the capacity of the iMac, really high and long (>1h) usage of the iMac will bring this problem up.

- Why this problem is for everyone ?
=> iMac have all the same cooling materials

- How can this problem be solved ?
=> An Software update of the fan/cooling controling will make this problem go away.

- What does this update need to do ?
=> Control the fans after the usage (if intense = blow more ; if idleing = go to lowest blowing setting )

- Tested ?
=> Yes. I installed the smc tool for controling the fan speed.
I turned it up for about 55% - 65% of the minimum speed fan and i never go up over 60°C also under full usage for hours. Compared to before when i was at >80°C.

- Why this problem came up ?
=> Because there is no auto regulation of the fan speed / usage.
=> It's blocked to the minimum speed fan and never changes.
Click to expand...

Hey there,

I got a 27" i7 that after about 30 min of gaming would start getting flickering and then blackouts. I will try regulating the fans to see how it goes. Though the GPU should hold at 80 c.

You right that most people who do not game will not have thier GPU beyond the standard temps so will never see the issue, not that it does not exist.

I'll try playing with the temps on mine to see how it goes.

Does anyone play games like wow for 2hrs + without setting the fans and not experience this? My point is that if people are playing games at 80C on the GPU and thier machines are fine, then by cranking up the fans on yours to bring it down to 60 is not really solving the problem. I would prefer to have a machine that work fine at 80 and then bring it down to 60.
 
Though i must add one thing. When my imac decides to have go into its flickering/blackouts with the GPU at 80c I have a 24 LED ACD plugged into the imac and that is perfect, not a flicker. So since the same GPU is powering the ACD why would it not be failing due to heat? Right now I play games on the Imac and just use the ACD to play them on while the imac flickers away and blackouts all the time.

Another assumption that i have is that the PSU might be at fault, at load it is on about 75 c. And as PSU get hotter thier efficency drops, so while the PSU might be powering the unit fine while cool, as it gets hot the might be struggling to power the LED.
 
MH01 said:
Though i must add one thing. When my imac decides to have go into its flickering/blackouts with the GPU at 80c I have a 24 LED ACD plugged into the imac and that is perfect, not a flicker. So since the same GPU is powering the ACD why would it not be failing due to heat? Right now I play games on the Imac and just use the ACD to play them on while the imac flickers away and blackouts all the time.

Another assumption that i have is that the PSU might be at fault, at load it is on about 75 c. And as PSU get hotter thier efficency drops, so while the PSU might be powering the unit fine while cool, as it gets hot the might be struggling to power the LED.
Click to expand...

Why doesn't your ACD second screen flicker when you plug it ?
=> As simple as your screen isn't near the heat in the iMac.
=> Try to heat up to 75-80 °C your other Screen and see if it flickers ;)

As for the games: I play wow and Aion for many hours ;( I know but i am hoocked.
 
SaSaSushi said:
Keep in mind that user forums are generally where those with issues go to post about them. It is still a very tiny minority of the i7 owners out there. If it were anything approaching a notable percentage of the machines being sold that were affected you'd be reading about it on tech news sites (and not just reports that folks have been reporting such problems to user forums). Apple would be forced to comment officially or issue a recall.

I'm at 5 days and counting with my i7 and have not experienced any flickering problems yet. I've gotten it pretty hot too.
Click to expand...


How do you know "it is still a very tiny minority of i7 owners out there"?
 
hakr said:
How do you know "it is still a very tiny minority of i7 owners out there"?
Click to expand...

I personnaly think everyone has that problem.
As EVERYONE has exactly the same model. It's the first which cam eout of same factory !

Why didn't it came up for some ?
Because it's only coming up when they use extremely strong the CPU and the GPU.
Which not all do.

Try playing a high resolution game for > 45 mins.
You'll see ;)
 
I received my i7 iMac on the 27th. It has a yellow gradient down the middle of the screen, so that only at the sides are the colors unaffected. Apple will be sending me a replacement, but are allowing me to keep this one until it arrives.

Last night, I put the iMac into sleep mode after 2 days of flicker-free use. When I woke it this morning, the screen began flickering with white bands. Occasionally, the monitor would reset. During this time, the iMac was practically idle, therefore high temperatures would have been highly unlikely. After a reboot, the flickering issue is no longer occurring.

Is it possible that this problem is being caused by a software problem with sleep mode?
 
Ghosti said:
I personnaly think everyone has that problem.
As EVERYONE has exactly the same model. It's the first which cam eout of same factory !

Why didn't it came up for some ?
Because it's only coming up when they use extremely strong the CPU and the GPU.
Which not all do.

Try playing a high resolution game for > 45 mins.
You'll see ;)
Click to expand...

With all due respect, Ghosti, I have gamed for one hour plus with this machine and not yet had any flickering issues. I do not play either of the games that you mentioned you're using. Still, I've put the GPU through it's paces.

I'm sorry about your problems and I hope you get them fixed. It's not a universal issue affecting all i7's with hot GPUs though.
 
SaSaSushi said:
With all due respect, Ghosti, I have gamed for one hour plus with this machine and not yet had any flickering issues. I do not play either of the games that you mentioned you're using. Still, I've put the GPU through it's paces.

I'm sorry about your problems and I hope you get them fixed. It's not a universal issue affecting all i7's with hot GPUs though.
Click to expand...

Not to be too personal, but what game did you play on ?
On which OS did you play ? Snow Leopard or Windows Vista/7 ?
 
Mine and many other people's have exhibited these symptoms while not doing anything that would stress the GPU. Mine did it while just web surfing in a room with an ambient temperature in the 50s.

And as to how widespread this is, given the low number of these devices actually out there to date (the Apple store I took mine back to told me it was literally the first i7 they'd laid eyes on), this is a lot of problem reports IMHO, esp. considering a lot of people wouldn't even notice the possibly separate yellow tinge issue. (The tech I spoke with speculated they could in fact be caused by the same thing, though this didn't seem all that likely to me.)
 
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