[geeks] Mac Pro 1,1 CPU Upgrade - failure?

[Nick B]

One thing to keep in mind, I'm pretty sure most of the MAC Pros use special
CPUs without the IHS.
Nick


On Sun, Dec 11, 2016 at 12:59 PM, Mark Benson <md.benson at gmail.com> wrote:

> On 11/12/2016 16:48, Andrew Jones wrote:
>
> This says the thermal junction between the CPU heat spreader and the
>>> heat-sink is bad. I took it apart, and found CPU-A heatsink wasn't
>>> totally touching the plate, or at least had made an incomplete junction
>>> (would explain a lot) but CPU-B looked fine. I redid both the CPU
>>> heatsink junctions, using bit more arctic silver in case my skimping had
>>> stopped it working. Reassembled it and... now it's even worse. The CPUs
>>> are at 57C and the machine crashes within minute of booting.
>>>
>>>
> New rub:
>
> I torqued down the CPU heatsink bolts 'very tight', but it doesn't seem to
> have made much odds.
>
> I can use Linux happily, but burnP6 is taking the CPUs cores from 38C to
> 58C in less than a few seconds. If I dick with the CPU fan rates (rev em up
> to 2000RPM) the CPU cores seem to sit at 58-60C and are stable in Ubuntu,
> and collapse back to 37 or so after I kill the processes.
>
> OS X last longer if I let the machine stand for a while, than if I restart
> immediately. This is thus a heat issue, I'm pretty sure. Feels to me like
> something vital is running a thread on OS X on one particular CPU core
> that's then overheating and blinking out. IF I, again, ram the fan speed
> up, it lasts longer, but still flakes out eventually. I manage to get the
> Mac Pro 2,1 Firmware update installed on the EFI ROM and also flashed the
> SMC ROM to a matching 2,1 revision version that's better able to handle
> 8-core setups. Still no luck, though. Even the OS X 10.6 Installer DVD
> locked up during the initial stages of the install.
>
> You want to use as little thermal paste as possible.  The coat should be
>> so thin it's not visible to the naked eye.
>>
>> Thermal paste has a better thermal conductivity than air, but it's much
>> worse than metal-to-metal contact.  The goal is just to exclude any air
>> from defects on the surface.
>>
>
> Right, will yank them off again next time I've got time and clean off the
> excess. I am using Arctic Silver (which is metal loaded) but I don't
> suppose it's THAT much better. Given the toque I applied it
>
> P.S. don't take the degrees C values too literally.  I don't think those
>> thermistors are calibrated against anything.  They're there to detect
>> catastrophic rises in temperature to avoid toasting the chip.
>>
>
> Noted, although the rate at which things go up and down is concerning.
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