ATI x1600 problem almost fixed!

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ATI x1600 problem almost fixed!

Hello there,

As you already know, there are frequent display artifact problems and in general GPU stability problems with iMac (and macbook pro!) models featuring the notorious ATI x1600.

My last attempt at fixing this problem was to check the GPU diode temperature, which was around 59 degrees Celcius. The video card stability tests that I made showed beyond doubt that graphics chip stability was compromised at this temperature. One program showed random video RAM errors suggesting GPU bus instability, and the other program found artifacts in under 10 seconds.

Therefore, I downloaded the wonderful freeware program called smcFanControl and adjusted the minimum fan speed to about first 2000 rpm and then 1500 rpm, yes there is more noise, but the GPU Diode temperature is about 44 degrees now and there haven't been any nasty crashes for a while, and on the boot camp the video card stability surpassed the one minute mark. And I haven't seen any crashes since then, let's see how far it will go, it's past one day and there is no sign of a storm yet. I also keep the LCD brightness as low as possible (around median) to avoid excessive heat and do not use graphics intensive screensavers just to be on the safe side.

Hope this helps somebody around here!

Regards,

--
Eray Ozkural
Researcher, Erendiz Superbilgisayar Ltd.

PS: The Apple Hardware Test cannot find any fault when the GPU is malfunctioning....

iMac 20" mid 2006, Mac OS X (10.5.7)

Posted on Jul 5, 2009 8:25 PM

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Answer 1

Jul 5, 2009 10:39 PM in response to examachine

I have that GPU in iMac (late 2006 17-inch Core 2 Duo). I've never had any problems with graphics "artifact problems" (or any other problems).

Thought I'd provide some positive anecdotal evidence...

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Answer 2

examachine Author

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Jul 6, 2009 3:42 AM in response to Kenichi Watanabe

Yes, but I wonder what does that show? That so many of us are mistaken in observing a design flaw? I guess not. Maybe it just shows that you are lucky. Good for you!

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Answer 3

Jul 6, 2009 4:20 AM in response to examachine

The only difference is that people with problems tend to post on forums to state that they have problems. People who do not have problems generally do not have any reason to post that everything is perfectly fine. Therefore, such anecdotal evidence is heavy skewed to the negative.

Also, when I do a Google search on "ati x1600 mac," most of the hits are about people over-clocking their X1600 and how to do it (not about problems). Because they are able to over-clock from the stock settings, that tells me Apple designed a fairly large safety margin into the design, since any over-clocking will increase heat and decrease reliability. I have not personally over-clocked anything, since I am happy with the stock performance.

(I see no evidence to justify calling it "notorious.")

So my guess would be that I am not particularly lucky, but you may be unlucky. Or perhaps your iMac's cooling system is not working as well as it should, since you say that increasing the fan speed improves reliability; maybe airflow is being blocked or hindered internally or one of the fans is not working properly. Or your iMac's power supply is becoming faulty. Or you are plugging it into an old surge suppressor (power strip) or one with too many other devices connected (overloaded).

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Answer 4

examachine Author

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Jul 6, 2009 10:46 AM in response to Kenichi Watanabe

I have not made any modifications to the system, or overclocked, I experienced exactly the same symptoms as many others. Can't be a coincidence.

And really, I don't need to hear a fanboy opinion that Apple never does something wrong. It might be a flaw with ATI. I don't care. Apple made a design mistake and I can't use the system for one of the very features I've bought it for: very low noise, since I prefer to use it right next to the vocal recording gear.

And you might guess that this happens after a long period of use, who knows maybe the fan is not effective as it was, and maybe I used it much more intensely than you did. I don't think it has anything to do with the power, what gives you such ideas? The power unit is not failing, why is there only a problem with the GPU heat, then, doesn't make any sense.

Please stop with your fanboy BS, I've had enough.

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Answer 5

Jul 6, 2009 12:12 PM in response to examachine

I don't see anyone else expressing an opinion either way... If you didn't want honest feedback, why did you bother posting?

I did not say Apple never did anything wrong. I'm just expressing my opinion (as you did yours) that this problem is not as widespread as you seem to imply, and that it is possible the cause is unrelated to the design.

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