Overheating Sawtooth PowerMac G4

[ephramz]

After installing Tiger when it came out and even after upgrading to 10.4.1, my Sawtooth PowerMac G4 with a 1 GHz Sonnet CPU upgrade card keeps freezing when it is doing processor intensive tasks (watching movies, ripping MP3's, video in iChat, etc.). I've repaired permissions and repaired the startup disk, did a memory check with Rember (all OK, some permissions needed repair, and some blocks of disk couldn't be repaired). I wondered if the CPU was overheating because of my processor upgrade card.

I opened up the case and the fan still seems to be running, although a little dusty. I left it running with the case opened and an external desk fan aimed at the CPU and whenever it crashes the CPU feels insanely hot (can't touch the heatsink for more than a second). Other times when I feel it it is sometimes hot, sometimes cool. I can't run any of the temperature monitoring apps like ThermographX since there is not temp sensor on my CPU.

Any ideas if this sounds like a processor overheating problem, bad memory problem, or software install problem? I've run without any external peripherals plugged in, and put a second fan inside aimed at the CPU heatsink, and it seems to be happening less now. Where is the fan intake since it is on the enclosed side of the box? It's been in the 90's+ here recently, so I'd be overheating too!

No obvious problems in the console logs, but where do I look for kernel panics?

Thanks for the help.

[Raven]

If you want to be able to check your cpu temp some more, check out Temperature Monitor It will let you at least check how hot it actually gets...

[trevor]

Why don't you swap your original processor back into the computer (I know that will be a frustrating slowdown, but maybe better than constant crashes?) and see if the problem goes away. If it does, you need to talk to Sonnet about a replacement card.

Trevor

[ephramz]

As I said, I can't run any of the temperature monitoring programs like Thermograph X, Temperature Monitor, etc. as this CPU has no temperature sensors available.

I'll try the CPU swap, and removing 3rd party memory as others have suggested.

Thanks.

[JDV]

That they have tested many, though no all, of their processor upgrade products with Tiger and have found them to be compatible. Of course, mere compatibility doesn't guarantee what happens when the processor is pushed very hard by the sytem, so there still may be a problem at the extremes, which is where ephramz reports having the problem. On the other hand, Sonnet also claims that their processors are much more heat-tolerant than standard processors, many being certified to operate properly at 85C. If something in Tiger is pushing it to temperatures that far beyond specs, this sounds like a serious problem; possibly one that Sonnet may want to know about. I am typically a bit leery of processor upgrade solutions, but Sonnet does have a strong reputation in this field. I'd certainly urge you to contact Sonnet's tech support people and describe this phenomenon; if it is something they don't know about, they should. On the other hand, they probably should have included system monitoring for the card, too, but apparently didn't.

Joe VanZandt

[ephramz]

Thanks for the advice, JDV and Trevor. After a day of swapping CPU's (still had the old 350 MHz one around), pulling memory, and USB/Firewire peripherals and cards, I pretty much had it nailed down to the Sonnet upgrade processor getting super hot when I did lots of processing. I even tried checking the processor temp with a medical thermometer, but it went off the 108 degree scale quickly! So I called Sonnet, and they said, "it happens, send the processor back, and we'll send you a new heat sink/processor combo".

It seems the later versions of the upgrade I have, the Encore ST G4, come with a heatsink with built-in fan, which mine doesn't have, so that might be why it was overheating.

Thanks for the help!

[Raven]

Its nice to see that some companies don't argue over and over before sending a replacement part. Thumbs up to Sonnet for having good customer support !