The 27-inch iMac Flickering Report

February 3rd, 2010

In the old days of CRT displays, I never, ever, got a perfect product. Except perhaps for the original 13-inch Apple RGB color display, every one of them was defective in some fashion. Now you can call me obsessive/compulsive, or just picky, but my eyes would discern the minor irregularities in screen geometry, where the supposedly rectangular picture would perhaps bend at one corner or another. From then on, my eyes would focus on that singular defect, and it would stick in the back of my mind, ever-present.

Now the era of LCD should have dealt the death-blow to such problems. For the most part, that’s true, but newer problems replaced the geometry defects. From limited viewing angles to imperfect color uniformity, LCDs have their own brand of troubles. Even if colors are right on, there may be dead pixels, but if you have too many of those, or they are in the wrong position on the display, you will usually be able to get a replacement from the dealer or manufacturer.

Now large LCD TVs and computer monitors are nothing new. Before Apple came out with a 27-inch iMac, they had (and still have) a 30-inch Cinema HD Display in their lineup, for a mere $100 above the price of the cheapest large screen iMac. It’s hardly worth the bother, since the 27-inch iMac, sporting a 16:9 aspect ratio rather than the previous 16:10 widescreen motif, offers the same number of horizontal pixels. And you get a powerful built-in computer as part of the package, so I wonder just how many 30-inch displays Apple is actually moving these days.

However, the 27-inch iMac had a somewhat troubled introduction. Some early adopters opened the shipping box, which, even though everything seemed intact and undamaged, revealed an iMac with a broken screen. Indeed, one of the first test units Macworld received arrived in a similarly damaged condition.

Although some might feel Apple has surrendered too readily to environmental activists and made shipping containers too thin and not sufficiently protective of the fragile LCD panel, that’s not actually true. I’ve seen boxes for 26-inch and 32-inch TVs that are no thicker, and they ship tens of millions of them without customer complaints about breakage.

Well, that problem, whatever the cause might have been, appears to have been resolved. But there are those troubling reports about display defects that persist to this very day. One disturbing symptom involves a yellow tinge, which is especially visible when you are viewing gray or white objects on screen. The other is even more peculiar, involving a flickering or tearing effect that appears at random.

It is fair to say that few LCDs will provide a 100% uniform color image. If you tilt your iMac, you will see minor variations in color conformity, even though the LED backlit panels Apple is using are of a higher grade than the ones most PC makers offer. If you achieve 99% perfection, that’s probably a good thing. But if a patch of discoloration is readily visible, Apple will certainly repair or replace your iMac. So far, the repairs involve swapping cables and even the LCD display. But some customers complain that they’ve had two or three repairs or replacements with little change, so you have to wonder whether they are simply unlucky or some other factor is causing those color artifacts. I don’t pretend to know the answer, but it does appear Apple is trying to do right by their customers.

The flickering is the most problematic, simply because some of the affected users say it may happen at intervals of days or weeks, not consistent enough to easily reproduce. Last December, Apple released its first fix, the 27-inch iMac Graphics Firmware Update 1.0. According to the support document on the subject, this particular update “applies to the graphics firmware on ATI Radeon HD 4670 and 4850 graphics cards to address issues that may cause image corruption or the display to flicker.”

Some customers reported that patch worked. Others didn’t. So this week, Apple came out with yet another fix, the 27-inch iMac Display Firmware Update 1.0, which is also designed to “address issues that may cause intermittent display flickering.”

Confusing? Well, they also recommend that you apply the graphics update ahead of the display update. If you’re not sure what you need, just use Software Update on your 27-inch iMac, and it will retrieve the required file. If you get the graphics fix, you’ll want to run it again after installation, to get the display patch.

If Software Update doesn’t list either of these updates for your 27-inch iMac, you probably don’t need them.

For the most part, the two fixes seem to have done the trick, although there are a few people who claim that the flickering problems have persisted after both updates, and even grown worse. For them and those who are afflicted with bands of yellow and other screen defects, Apple says “contact AppleCare or an Apple Authorized Service Provider.”

In all fairness to everyone, the number of people afflicted may be quite small. But some of them are extremely vocal, reporting the ongoing soap opera with their iMacs on various discussion boards, including Apple’s. The folks who have no problems, such as your humble editor, simply get their work done and don’t usually concern themselves with such complaints.

Contributing to the concerns is the fact that the new iMacs remain hot selling products. The 27-inch iMac delivery delays briefly extended to three weeks amid unconfirmed rumors that Apple had halted production. After Apple issued an official denial to The Wall Street Journal, delivery timeframes improved to two weeks. A coincidence? Or maybe an indication that Apple is finally getting a handle on production delays, regardless of the cause.

| Print This Article Print This Article

11 Responses to “The 27-inch iMac Flickering Report”

  1. dfs says:

    My 27-in. iMac arrived on Dec. 18 and have used it daily since then. Not a single flicker in all that time. I do have a yellowish tinge on the bottom of my display, which only became evident when I used a special test page, in normal use I hadn’t seen it at all. I suppose that if I were some sort of graphics or photography professional I’d hit the roof and demand that Apple do something about it. But for my purposes it would have to be a lot worse before it would bother me. Its effect on my use and enjoyment of this Mac is zero.

  2. After a month of use, my 27-inch i7 has started showing the yellow tinge. The bottom right quarter of the screen is noticeably warmer than the rest. Sometimes it looks yellow, sometimes brown, like something that’s been left too long in the smokers’ lounge. I have to say that it’s damned annoying in a machine that cost over two grand, and was touted by Jonathan Ive as being all about the screen, all about the computer not getting between the user and his vision.

    I haven’t decided what to do about it yet, as Apple doesn’t seem to have decided either, but I’m NOT happy about it.

    • @William Timberman, I probably should have said that it in all other respects, this iMac is far and away the best computer I’ve ever owned or used. Also, I paid $1000 for a 15-inch studio display when I bought my Cube nine years ago, and it had one stuck, bright red pixel, almost dead center. I agonized over that, too, but in the end just got on with business.

      I still have the thing, and its still as useful as it was on day one — it’s attached to my old G5 tower now — and I haven’t been conscious of seeing that pixel at all after the first month. My first iPhone also had developed a brown spot after a year or so, and an intermittent dead band in the touch screen. Neither dampened my enthusiasm. Maybe I’ll get used to the yellow, too.

      And tell Steve Jobs that I’m already in line for my iPad. I may be one of those suckers that’s born every minute, but hey, life is short.

  3. dfs says:

    As a footnote to Gene’s article, it’s worth pointing out that Apple reportedly is offering a 15% rebate to purchasers of defective 27-in. iMacs. See

    • @dfs, To clarify: You get 15% extra when you return the iMac for a refund because of these defects. It’s not that anyone who has a problem magically gets a 15% check for the inconvenience.

      If true, it only goes to show once again that Apple is really trying to get this situation resolved and satisfy customers.


  4. My preordered 27-inch i7 has an occasional case of the flickers … but it’s still the most wonderful computer I’ve owned.

  5. Kevin says:

    My 20″ iMac (late 2006 edition) has the same flickering symptoms, which started about a year or so ago.

    I keep it running cooler by speeding up the internal fans via smcFanControl. That seems to help, but it has not cured the problem

    Will the 27″ firmware update be applicable to old iMacs as well?

  6. dfs says:

    Nobody knows exactly what these firmware updates do. One theory is that Apple has determined the graphics cards on the 27-in models run too hot, and that they are intended slow down the graphics card, which would have the effect of reducing the heat.

    • @dfs, Easily determined with iStat Pro, a Dashboard widget that displays all sorts of info, including the temperature readings of various internal components, such as CPU, GPU DIode and GPU Heatsink. Surely if there was a heat-related change, you’d see it there. I didn’t notice any material effect before and after the two firmware updates. Then again, I never had the problem.


Leave Your Comment