Q: New iMac 27inch screen flickering/tearing/shutoff

I was wondering if a few of you here who have a little more experience and knowledge regarding graphics cards -- such as Sonic99, Schwa72 and Panzuita -- could answer a question for me:

How does the NVIDIA GeForce GT 130 graphics card -- which is in the discontinued 24" iMacs -- compare to the ATI Radeon HD 4850 graphics card that is in the i7 iMacs?

I'm not trying to start a graphics card war here, I am just curious how my new i7 machine will compare graphics-wise with my child's 24" iMac -- once it FINALLY gets here.

Thanks!

So, it rumbles on. Personally, I don't suspect a ups would have stopped my 27inch i7 going back to Apple. I'm happy back on my 24 inch core duo which I bought in Aug 2007 and it hasn't blinked once. Nor have the 4 MacBooks, 1 mac mini or 2 iPhones that I have bought since then. All have been perfect.

What happened to quality control here? The rush to be ready for the holiday season? My i7 had the flickering problem, yellowed lower screen and the hard drive which made stomach rumbling noises. Maybe the yellow problem and flickering are one and the same, but 2 problems on one machines, and previously zero problems on 8 machines for 2 years or so.

Since being converted to Mac I've also encouraged various friends and relatives as well. Same story, perfect hardware in all cases. The only issue I've seen is a software problem between Snow Leopard and Microsoft Office for Mac, which was eventually fixed by 10.6.2.

This avoidance of public admission of a problem by Apple, I find acceptable when they fix things that occur reasonably quickly. You don't know exactly what's going on but you have faith. My faith is being tested. My i7 was originally delivered on Dec 1st and went back on Dec 14th. The replacement is currently stated as for delivery on Jan 5th. I've also been studying the Squeaked statistics and I'm wanting to see that the problem is fixed. I'm also wondering if the person with Quality responsibility for that production line is still in a job?

Hi there, i am joining the club as well, hanging on the phone with support at the moment. Got my 2nd Imac 27 inch I7 this friday, started it up yesterday, spotted kind of a jellow glow in the middle of the screen, but thought, it has to do with warming up maybe.. then worked on it the whole day, noticed it got quite hot on the top of the imac.. I could nearly fry an egg on it. The support guy saids they will ship e new one again.. THE 3rd ONE!!! But it will be next year in januari 2010, this is really really frustrating. But i will keep my hopes up.. buying online is not helping me out here.. i cannot change it for a new one at a licensed apple store.. so i am doomed to wait for UPS AGAIN!...

This is message 1400 somewhat in this topic... isnt APPLE WAKING UP!?!?!?!

Please help me out guys... this is my first MAC, i had high hopes for this product but negative vibes are bashing my positiveness..

this has cost me 5 days now.. copying files.. installing CS4 etc.. wiping it.. sending it back.. reinstall new one.. etc. etc.

APPLE THANKS A LOT for giving me such a crap product

Hi all,
I am a new Mac switcher and a proud owner of a brand new iMac 27'.
However, this nice machine has the flickering display disease... How frustrating this is!
I plan to contact the Apple Care assistance, but I'm very surprised that Apple did not officialy react to this "bug".
I'll let you know the result of my actions.
Otherwise, this machine rocks!
Gerald,
Paris France

Message was edited by: grazu

as i mentioned before.
screen flicker and black out only occurs AFTER imac has been waken up from sleep mode.

i let the computer running for 3 days now without going to sleep. and so far NO PROBLEM what so ever...(has screen saver and dim out the screen at night, but the computer was ON for 3 days without sleep)

sounds like it could be sleep/wake related
makes me feel like its a software glitch!

Aftersales guy contacted me (Paul Vostert) after waiting 30 minutes on hold with the tech guy in Maastricht Holland...

He is sending me an email with a waiver, a sort of swap contract. I am refusing to send this one back and waiting for the 3rd one that they are shipping somewhere in january week 2 or 3..

He made a deal, apple is shipping one over from China.. have to sign a contract for this telling that upon delivery of the new unit i have to contact Apple again to engage shipping of the old unit. So i have a day to migrate from one to the other Apple Imac 27"... so.. i can still work on this one until the new one arrives..

Normally apple arranges a direct pickup of the old one, and you'll have to wait for the new one to arrive.. for me in this situation (3rd Imac since purchase) this is absolutely out of the question.

Nice gesture of Apple aftersales i have to say, but i would rather like to receive a thouroughly tested unit.

I am 100% sure it is the faulty 4850 getting way to hot.. could be a driver issue or Solder issue on the mainboard.. the stuff is packed together with a tiny fan having a real hard time cooling it all down..

PLEASE OH DEAR M. OF G. let this new one be OK!!!!!

Otherwise i have to go for the full refund

This link:

http://www.macworld.com/article/145075/2009/12/imacdelays.html?lsrc=nl_mwweek_hcbstories

appeared in MacWorld Weekly today.

Steph - An iMac Girl

Message was edited by: Stephanie Craxford

Hi Steph,

That article was posted on Dic 14, it's been on for a while...

fa

Hi!
Mine has flickered with blackouts twice since I got it 7th of December, first 11th of December and second 19th. Both times, the computer was turned on the same day (never use sleep mode) and was not hot al all. In fact I have been playing COD4 without this problem and the computer reaching very high temperatures.
The first time I turned off and on the computer and dissapeared. The second time I did nothing and after 20 minutes the problem went off.
Since Apple Tech Support was not able to explain this behaviour I requested a new i5 hoping this one will came with no issues.

For some, the problem is hardly noticeable and trivial, and for the moment that is me; albeit, at first, I was highly stressed about the thought of a malfunctioning, defective machine.

And for others, the display flickering, blackouts, and the yellow tinge are relentless and unforgivable. For these people, the roll-of-the-dice iMac exchange is the only solution.

At the moment, when my display starts playing up, which varies from sometimes daily, to going a whole week, my solution is to put the display asleep for a few seconds, then revive it, and the display problems seemed to be cured.

I have installed the BetterTouchTool to go with the MagicMouse, and use a four finger click to sleep the display.Then I move my mouse, the display comes back on, and the display hiccups seem to disappear for another interminable period. And it works immediately! Go figure. Others have reported the same when they put the whole computer to sleep.

If this display problem was line voltage related, I don't think this "sleep step" would be a reliable cure. Likewise, temperature issues with the graphic card would be unaffected by a brief interruption to the display. As for hardware issues, excluding yellowish LED backlighting screen graduations, and dicey hard-drive noises, flickering issues and the like would probably portend component failure, eventually getting worse toward complete inoperability. I think we would have seen (reports on this forum) a few cases of 27 inch iMacs failing to display anything by now because of deteriorating component failure, possibly directly involving the screen components themselves. Of course, this is just my speculation. Another week from now, I could be one of those unfortunate iMac owners that is plagued with continuous display problems, or other stuff.

Another thing to consider is the almost universality of the problem. Every production week seems to be affected. If it was a bad batch of components, surely we would start seeing production runs by now (week 51) where those machines would not even be reporting flickering and, thus, not even showing up on this forum. I know some, or maybe a lot, are reporting no problems, whatsoever. Perhaps, their setup or operation of the iMac somehow makes their machine invulnerable to the display problem. Incidentally, it wasn't until I downloaded some software and tried to run it that I got the flickering and blackouts. Coincidence? Maybe. Don't ask me to recall that software. Maybe by running certain software, perhaps graphic related, some bug insinuates itself into the OS setup that gives rise to this problem.

And that is the underlying crux of the problem. With something so random, how to initiate the flickering, to get some sort of predictability and, therefore, the cause, whether hardware or software related. The commonality of all those affected seems to be having a 27 inch screen with the ATI GPU. Seems like driver (113-B9110C-394) is the issue. Some have reported no issues when running Bootcamp, and Windows 7. I know, I know. Some have also reported issues when running Windows 7. Who to believe? What to believe?

But, so far, from my experience, this problem seems to be a software glitch. I am no electrical engineer, but perhaps some GPU values or settings drift with time, and have to be reset by way of interrupting the display screen, either by shutting down, or sleeping it, which sets the drivers to a default value, correcting the blips for another cycle.

Anybody want to highlight the GPU software glitch theory, values drifting, corrupting, etc? Or completely debunk this theory?

5 days into using my i7 and so far no flickering or blackouts( knocks on wood).

Hope I got a good one.

:crosses fingers:

I agree...seems like a software issue to me as well. Well written!

This all reminds me of when the iPod Touch was first released. There was a lot of angst on these boards about bad pixels, screen discoloration, batch numbers, and multiple returns. Back then, as now, A* never formally acknowledged any of these issues existed despite repeated demands that it do so. As I recall, A* eventually just issued an update without making any comment.

I don't doubt many posters here are having legitimate problems with their iMacs--but you have to believe that some percentage of these complaints are coming from trolls and Windows fanboys. Just look at online reviews of hard drives. Nobody would ever buy an HD if all the reviews were legitimate.

"plus ça change, plus c'est la meme chose"

Message was edited by: inandoutofgrace

Anybody want to highlight the GPU software glitch theory, values drifting, corrupting, etc? Or completely debunk this theory?

Certainly not debunking but find it hard to accept when I have a very satisfactory i7, along with many others. My thoughts are more to do with component tolerances or quality of a host of connections affecting timing. That is not to say that software or firmware updates are unlikely. Of course I am tempting fate yet again in saying my i7 is fit and well.

Just checked Software Update and there was a firmware update to address this issue. Seems to be working for me so far...so far anyway. I hope this fixes all your systems as well. Man Apple makes it hard to defend them when my Windows 7 friends come over and see this haha shizzle.