iMac restart randomly, much more frequently when play WoW and SC2

[duyphong]

Hello everyone, I have a very annoyed problem that even I brought my iMAc to the Genius Bar 2 times, they cannot identify the problem is.

It happened (well more regularly) when I play WoW and SC2 on both Mac OSX (10.6.8) and WIndows 7 bootcamp, the comp just suddenly auto restart itself. I have updated latest driver on both operating systems, check out all the discussion to unplug all USB, plug directly to power point, reset Vram (or watever it is), format, reinstall the OSX and windows... The problem is still exist...

The first time I brought to iMac store, they change a new motherboard because they believe there is problem with transistor. Then the problem was still exist, then I brought second time. This time they said they cannot identify what is the issue is after running all complicated test... and asked me to bring back home to check it out again. Once I turn the machine on and play the game, the comp restart immediately on the character selection...

This is the first time I buy the iMac and it turns out really disappointed. Would you guys please point out any solution for my problem? whether I can play on OSX or Windows...

My iMac is 27" intel core i3, graphic card ATI 5670

Thanks heaps!!

 

[KylePowers]

Is it restarting with proper shutdown and whatnot? Or is it just instantaneously turning itself off?

Have you checked your CPU and/or GPU temperature while gaming? Maybe the CPU or GPU is getting too hot and it's shutting down the iMac before it gets damaged?

//iMac noob, just guessing

 

[duyphong]

hey KylePowers, thanks for the reply, it is just instantaneously turning itself off. I believe it cannot be the temperature. I have just turned on the machine, log in the game WoW , and it restarted suddenly while choosing character without any warning.... Everything happened like within 3 mins... so yeah....

 

[duyphong]

Does anyone have any idea?.... I am really clueless after all these...

 

[fivedots]

Do you have 3rd party RAM installed? Could be improperly seated/not in all the way. The factory RAM clicks in rather well, my 3rd party stuff is more difficult to install.

My machine would simply power off with it installed, but only when using Photoshop.

 

[duyphong]

I havent installed any Ram at all. This Mac just come with all standard features.. Core i3, ATI HD5670, 4Gb ram.

DO you think there is something wrong with the graphic card? The issue arised when I start playing WoW. I do not think the game client has any problem because I have just re-installed it, no addon, all fresh and WoW is a worldwide game. There should not be any problem with the game client...

 

[leman]

I have a similar problem. My iMac randomly freezes, there is no warning, no log entry, no kernel panic, the computer just stops where it was (stationary display image remains visible, the current sound sample in the sound buffer is repeated indefinitely) and I have to turn it off by pressing the button. Till now, it only happened while paying WoW and utterly at random (it can happen at the ten'th minute of gaming or after multiple hours).

In my case, I did install additional RAM from corsair, but all the memory tests I tried turned out negative. I run Apple Hardware Diagnostics Tool several times, I also run memtest for 14 hours straight - they both find no errors and do not crash. I have even written a dummy application which does some meaningless (but CPU and memory-intensive) statistics on 10Gb+ datasets and run it half a day long - no crash.
So its either a really very subtle RAM problem or some issues with GPU. I am really a bit puzzled here...

 

[FrankHahn]

Have you had your hard disk checked? A failing hard disk (bad sectors) can cause the freeze or restart of a computer.

 

[duyphong]

I have run Disk Utilities.... it was shown nothing wrong. And I believe that Apple has run all the relevant tests that they required to... still shown no problem. The comp crashing today when I was watching movie, surfing the net as well... SO annoying.. I probably should take it to an authorised service centre rather than taking it to an Apple store where they can test the comp in reality and not use all those stupid tests.