[HELP] How can I detect what caused a crash on OSX?

[iamdarkyoshi]

Troubleshooting this stupid 24in, Early 2009 iMac with 4GB DDR2, Core2duo at (basically) 3ghz, and a GT120.

 

Whenever I try to run unengine heaven, it will crash after a couple seconds. Full shutdown crash. I have already tried reflowing the GPU with no change.

 

Thinking it was a weak PSU, I tried the PSU from a working iMac. No change. HDD SMART data is fine. Tried both RAM sticks, and each individually. No change.

 

I have already tried running

yes > /dev/null & yes > /dev/null &

to stress both cores. The machine has no issue with me doing this, it handles this fine.

 

Is there any way I can log the crash? Occasionally when I run unengine heaven and it crashes, the benchmark closes first, then the machine dies. I managed to capture it on video: 

 

Spoiler

 

 

 

[byalexandr]

Maybe the GPU memory is at fault? Perhaps it crashes once it loads the GPU memory? Or maybe the VRMs to the GPU are dead?

[iamdarkyoshi]

1 minute ago, byalexandr said:

Maybe the GPU memory is at fault? Perhaps it crashes once it loads the GPU memory? Or maybe the VRMs to the GPU are dead?

Not sure. It runs unengine heaven at a reduced resolution for LONGER, but it still will shutdown.

[byalexandr]

Just now, iamdarkyoshi said:

Not sure. It runs unengine heaven at a reduced resolution for LONGER, but it still will shutdown.

Yeah it sounds like the power delivery is shot on the GPU. Especially since it just turns off.

[iamdarkyoshi]

Just now, byalexandr said:

Yeah it sounds like the power delivery is shot on the GPU. Especially since it just turns off.

That is what I am thinking. Shame I have no other GPUs for this machine. It seems like someone has already recapped the motherboard, which is odd........

[byalexandr]

Just now, iamdarkyoshi said:

That is what I am thinking. Shame I have no other GPUs for this machine. It seems like someone has already recapped the motherboard, which is odd........

The more you add the more I think it is in fact the power delivery

 

Is it just a PCI-E add in card or is it soldered to the main board? I know iMacs are weird...

[iamdarkyoshi]

Just now, byalexandr said:

The more you add the more I think it is in fact the power delivery

 

Is it just a PCI-E add in card or is it soldered to the main board? I know iMacs are weird...

It has one of those interfaces that has the notch in the middle.

 

But this machine uses DDR3, and the other iMac that I got to fix (which I had two matching spare GPUs for, both needed a reflow and BOTH work now) uses DDR2 but looks to use an interface that looks like PCI-e but smaller. Dafuq.

[byalexandr]

Just now, iamdarkyoshi said:

It has one of those interfaces that has the notch in the middle.

 

But this machine uses DDR3, and the other iMac that I got to fix (which I had two matching spare GPUs for, both needed a reflow and BOTH work now) uses DDR2 but looks to use an interface that looks like PCI-e but smaller. Dafuq.

So it's PCI? Or maybe some proprietary connector Apple made?

[iamdarkyoshi]

1 minute ago, byalexandr said:

So it's PCI? Or maybe some proprietary connector Apple made?

Interface on the DDR3 machine looks like this (although not the same GPU) 

The other machine (with DDR2) uses GPUs like this one:

 

The DDR2 machine manages framerates WAY ahead of the DDR3 machine (when the DDR3 machine works)

[byalexandr]

Just now, iamdarkyoshi said:

Interface on the DDR3 machine looks like this (although not the same GPU) 

The other machine (with DDR2) uses GPUs like this one:

 

The DDR2 machine manages framerates WAY ahead of the DDR3 machine (when the DDR3 machine works)

Oh! It's a mobile GPU, that's why.

 

This one might work, idk though: http://www.ebay.com/itm/ATI-Mobility-Radeon-HD-3670-MXM-II-256MB-GPU-Video-Graphics-Card-/151625712976?hash=item234d98c550:g:~aEAAOxyVtxSL9cl

[iamdarkyoshi]

1 minute ago, byalexandr said:

Oh! It's a mobile GPU, that's why.

 

This one might work, idk though: http://www.ebay.com/itm/ATI-Mobility-Radeon-HD-3670-MXM-II-256MB-GPU-Video-Graphics-Card-/151625712976?hash=item234d98c550:g:~aEAAOxyVtxSL9cl

Not sure if the GPU is at fault though... I will ask the store owner tomorrow if he has any more GPUs that would fit in this machine (they are his iMacs)

[byalexandr]

Just now, iamdarkyoshi said:

Not sure if the GPU is at fault though... I will ask the store owner tomorrow if he has any more GPUs that would fit in this machine (they are his iMacs)

Yeah I would do that, just rule as much stuff out as you can. I really think it's the GPU though.

[iamdarkyoshi]

Just now, byalexandr said:

Yeah I would do that, just rule as much stuff out as you can. I really think it's the GPU though.

I think its apple.