5,1 cpu tray in 4,1 MP. Fans won't stop?

InuNacho

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Apr 24, 2008
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I just swapped the CPU tray in my 4,1 with a 5,1 and now the fans are running at full blast non-stop. I've done the 4,1 -> 5,1 upgrade so and I figured thats all I'd need but apparently I need a bit more assistance in my upgrade.
How can I go about turning the fans down? I've noticed that the Mac Pro fan control does nothing.
 

tsialex

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Jun 13, 2016
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I just swapped the CPU tray in my 4,1 with a 5,1 and now the fans are running at full blast non-stop. I've done the 4,1 -> 5,1 upgrade so and I figured thats all I'd need but apparently I need a bit more assistance in my upgrade.
How can I go about turning the fans down? I've noticed that the Mac Pro fan control does nothing.
it's a know issue, 2009 and 2010/12 trays are not interchangeable, SMC mismatch version. Since SMC from the tray can't talk to SMC from the logic board, no Fan control app works.

No one knows how to update the SMC on 4,1 tray/logic board (1.39f5) to the same on a real 5,1 Mac Pro (1.39f11).

You have to exchange for a real 2009 tray or change your logic board to a real 2010/12 version.
 
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InuNacho

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Ah bummer, I got a pretty decent deal on a complete hex 3.46 5,1 board and thought it'd work without any actual research. Guess now I'll just take out the CPU, delid, and put it in my old 4,1 tray.
Thanks for the help anyways fellas.
 
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handheldgames

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Apr 4, 2009
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Ah bummer, I got a pretty decent deal on a complete hex 3.46 5,1 board and thought it'd work without any actual research. Guess now I'll just take out the CPU, delid, and put it in my old 4,1 tray.
Thanks for the help anyways fellas.
a 5,1 logic board is about 125 on ebay.
 

tsialex

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Jun 13, 2016
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Ah bummer, I got a pretty decent deal on a complete hex 3.46 5,1 board and thought it'd work without any actual research. Guess now I'll just take out the CPU, delid, and put it in my old 4,1 tray.
Thanks for the help anyways fellas.
You only need to delid for 2009 dual processors trays, btw.
 

h9826790

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As said, it's a known issue. Do a search and you'll find many threads on this.

However, It's my understanding with the utility Macs Fan Control (https://www.crystalidea.com/macs-fan-control) you will be able to manually control the fans.

https://forums.macrumors.com/threads/mac-pro-5-1-upgrade-smc-conflict-fan-control.2062360/

Lou
No, cannot.

MacsFanControl control the fans by setting the associated SMC key. When the SMC mismatch, MacsFanControl doesn’t work.

It’s more powerful then most of other fan control software just because it set the target fan speed SMC key, but not the minimum fan speed SMC key. This will completely override the system protection, allow the user set lower fan speed than the system commanded.

However, this approach won’t work when the whole SMC stop working.
 
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tsialex

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Jun 13, 2016
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Is there any need to put in the logic board? The big sticked thread seems to indicate that I can drop in the hex without swapping the entire logic board.
On a single CPU tray:
- unmount the heatsinks from the trays
- clean the new processor removing old thermal paste from it and the heatsink
- swap processors
- apply new thermal paste to the processor
- remount the heatsink
- install the tray on the Mac Pro

No delid needed.
 
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parrotgeek1

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Jun 14, 2016
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it's a know issue, 2009 and 2010/12 trays are not interchangeable, SMC mismatch version. Since SMC from the tray can't talk to SMC from the logic board, no Fan control app works.

No one knows how to update the SMC on 4,1 tray/logic board (1.39f5) to the same on a real 5,1 Mac Pro (1.39f11).

You have to exchange for a real 2009 tray or change your logic board to a real 2010/12 version.
If only someone could dump SMC firmware from the logic board I would be able to make an update
 

minifridge1138

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Jun 26, 2010
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A single cpu tray from a 4,1 uses lidded processors.
If your 5,1 tray has lidded processors, then you don't need to delid them.
If your 5,1 tray has de-lidded processors, then there is no way I know of to put them in the 4,1 tray.
 

parisinvest

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Dec 24, 2017
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Paris
First time I’ve heard of this occurring.
Well done.
as i know the 4,1 and 5,1 are the same chipset same configuration same power, only smc are different, and yes you can downgrade and upgrade the logic board, once you have the same smc between the mortherboard and cpu tray, the fans will run normally.