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.

[CanadaRAM]

Originally Posted by 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.).

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.

Call Sonnet

They had a problem a while back with insufficient transfer from the CPU to the heatsink. On their advice only, you may need to remove the heatsink, clean it, and reapply some thermal compound like Arctic Silver. But I stress -- do so only after clearing it with Sonnet tech support.

Of course, cover all of the other, easier bases first: Remove third party RAM and test, remove extra USB and Firewire peripherals, etc.

[ephramz]

Thanks for the advice, CanadaRam. 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. 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!

[iowacity]

I had the same problem with my sawtooth G4 and a 1.2 Ghz processor upgrade that I bought from OWC. They sent me a new one very quickly and I'm running well now.