Welcome to the MacNN Forums.

sek929 · Jul 9, 2008, 11:22 AM

This has only happened twice, but under the exact same conditions and two days in a row.

While playing Command and Conquer 3 in XP (Core 2 Duo 2ghz, ATI Radeon HD2400) and after a half hour to 45 minutes the computer unexpectedly restarts back into OSX.

Now I have read that some Al. iMacs suffer from a design flaw in the temp sensors that shut the computer down when it gets to hot. The thing is, even under heavy gaming in C&C3 or COD4 the CPU temp rarely crests 70º Celsius. Well within the bounds of the machine from what I've read.

Something to worry about, or something inherent in XP under Boot Camp?

I've had a dozen apps running at once across two screens in OSX, temperature around 70º Celsius and it's never shut down.

sek929 · Jul 10, 2008, 11:45 AM

Anyone?

Bueller?

ghporter · Jul 11, 2008, 05:29 PM

It sounds more like an issue with Windows and how it handles the fans (and thus temperature) than an issue with your iMac. While other games or even bunches of apps at the same time may not cause a problem, whatever it is that causes it manages to get Windows' attention while you're playing Command and Conquer.

imitchellg5 · Jul 11, 2008, 05:30 PM

Could be an SMC problem. Try and reset it.

sek929 · Jul 14, 2008, 12:22 PM

Well it happened again.

This time in OSX with only Safari and Adium running. Temp monitor said only 60º Celcius.

Happened as I was looking at the dashboard.

I'll try the SMC reset a bit later.....I'm starting to worry she'll need to be repaired.

sek929 · Jul 14, 2008, 02:19 PM

Did the SMC reset as described by Apple.

Rebooted into XP, played C&C for a good 10 minutes and it restarted.

I really hope this is a problem with C&C and not my iMac, it is under warranty but it's a huge pain in the ass and I will miss it the second I send it in for repairs.

ghporter · Jul 14, 2008, 05:11 PM

I know this may be a challenge, but try to NOT play Command and Conquer for a day. See if ANYTHING out of the ordinary happens in Windows. If not, that pretty much points at C&C (and how it interacts with Windows).

sek929 · Jul 14, 2008, 05:15 PM

Can-do. I've been able to play COD4 (which is waaaaay more graphically intense than C&C) for over an hour at a time with no problems.

The key this time was the SMC restart meant having my computer off and unplugged for a bit (made myself a sandwich in the meantime) so even when it restarted the top of the iMac was barely warm, and it's usually pretty warm.

Too bad, I was getting far in the campaign too....

sek929 · 07:43 PM

Update

It did it again, twice.

This time while watching a movie full-screen in Front Row. SMC fan control was running and the computer never went above 50ºC.

What say you? Time for a trip to my nearest Apple Store?

ghporter · Aug 13, 2008, 08:07 PM

Yeah, take it in. That's just not right.

Big Mac · Aug 14, 2008, 03:42 AM

Spontaneous restarts have classically been a sign of a bad power supply.

P · Aug 14, 2008, 08:54 AM

Yes, but if they are related to specific software, it could be a GPU thing.