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pdafan

macrumors regular
Original poster
Aug 2, 2011
100
13
Was handed over an old Mac Pro Early 2009 with dual CPU.
The machine is able to boot up and work nicely but shortly after a while (5 secs into desktop), 4 fans will start to roar loudly
Booster 1 and 2 at around 5200 RPM
Intake and Exhaust at around 2700 RPM
Expansion slot and Power Supply normal at around 700.

The CPU temperature are pretty normal at around 40-60 deg celsius.
I borrowed a friend's CPU board (Early 2009 too) and fitted on to my motherboard and it was quiet (booster 1/2 at 1100RPM, the rest around 600-800 RPM).
This seems to prove that my Mac motherboard is fine. Problem lies with the CPU board.

Would like to add on that no CPU upgrade was done. Factory fitted BTO/CTO.
Tally with the spec label at the back of Mac Pro.

Can I seek expertise on how I can pin point the problem source and address it?
Thanks much
 
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If that's the stock config. The thermal paste should dry up already. May be you can re-apply the thermal paste and see if that make any difference.

Up to 60C with max fan speed after just log in to desktop in fact doesn't right. That's a good temperature, however, with that high fan speed, and the CPU's are not under stress, the temperature should be a lot lower.
 
If that's the stock config. The thermal paste should dry up already. May be you can re-apply the thermal paste and see if that make any difference.

Up to 60C with max fan speed after just log in to desktop in fact doesn't right. That's a good temperature, however, with that high fan speed, and the CPU's are not under stress, the temperature should be a lot lower.

Thanks for your advice. 60C is not the temperature right after start up.
The temperature is only 35C.
I used the macfan control to base on ambient. After sometime then the temperature rises up to 40-60C. That is why I can't pinpoint the problem and I cannot understand why the fan can spin so loudly.
Anyway I will redo the thermal paste and how it goes.
 
Thanks for your advice. 60C is not the temperature right after start up.
The temperature is only 35C.
I used the macfan control to base on ambient. After sometime then the temperature rises up to 40-60C. That is why I can't pinpoint the problem and I cannot understand why the fan can spin so loudly.
Anyway I will redo the thermal paste and how it goes.

Can you post a screen capture about how you set the fan profile? It may actually the cause of the high fan RPM.
 
Can you post a screen capture about how you set the fan profile? It may actually the cause of the high fan RPM.

I think I found the problem but not exactly know what it means.
The entire CPU A section is missing (from iStats Menu)

From the About This Mac, it shows 2 x 2.93Ghz Quad Core Intel Xeon.

So what does this mean? CPU or board or heatsink fault?
 

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I think I found the problem but not exactly know what it means.
The entire CPU A section is missing (from iStats Menu)

From the About This Mac, it shows 2 x 2.93Ghz Quad Core Intel Xeon.

So what does this mean? CPU or board or heatsink fault?

Yes, possible the missing temperature reading cause the system to spin the fan to 100% as precaution.

Anyway, if that reading is from the CPU itself, open it up, reseat the CPU A, and redo the thermal paste, may able to fix he issue.

Before you do that, may I know if that's the stock CPU?
 
I have re-seated CPU A with fresh thermal paste. Does not help. It is the stock delidded CPU X5570.
About This Mac still shows 2 x 2.93GHz Intel Xeon.
Could it be the heat sink or sensor issue? Hopefully it is one I can just replace the heatsink
 
I have re-seated CPU A with fresh thermal paste. Does not help. It is the stock delidded CPU X5570.
About This Mac still shows 2 x 2.93GHz Intel Xeon.
Could it be the heat sink or sensor issue? Hopefully it is one I can just replace the heatsink

TBH, not sure, because I assume the CPU diode temperature is coming from the CPU itself, and the heatsink temperature is coming from the heatsink, and now both are missing.

Anyway, did you try SMC reset yet?
 
Hi h9826790,

I did the SMC reset and the CPU A set appeared!
No more loud fans.

Earlier I did the SMC reset before reseating the CPUs and that did not work.

So it went working nicely for the next few reboots where I reformatted the HDD and installed a fresh OSX.

Then I took out the CPU board and inserted a few strips of RAM. Slotted in and the loud fans came back :(.
CPU A went disappearing again.

Really strange behavior.

Is there any app/utility that can confirm the presence of CPUs, particular CPU A?
 
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I have the exact same problem on my Mac Pro 4,1 upgraded to 5,1.. My CPU A randomly appears and disappears as seen on this iStat Menu history.
CPU A - Heatsink, CPU A - Tdiode
CPU B - Heatsink, CPU B - Tdiode
 

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An update.. My Mac Pro was a 4,1 -> 5,1 upgrade. Where I also upgraded the CPU's from E5520 to X5690.
Though it didn't help to downgrade the CPU's again, the issue still occured.

Then I removed all but two ram sticks, all PCIe cards, all extra harddrives and changed the motherboard battery.
Bootet it up, launched geekbench, let it run, then afterwards launched handbrake and encoded a DVD.

It's been up and running for now 30 minutes without the fans spinning up crazy, which is new. Before the fans would spin up a few minutes into OSX was loaded.
[doublepost=1486314611][/doublepost]My next step, is to turn it off again, and insert all ram sticks again, the harddrives, and the CPU's. and see what happens.. Maybe it was the battery on the motherboard?
 
Final results, both CPU's, harddrives, and ram sticks are all back in place. Seems to work perfectly..

So, to sum op, seems like a new battery on the motherboard is all it takes. I had the power unplugged.
 
Perhaps the fan connector of the CPU cooler has a connetion problem. This is a common problem, when using lidded CPUs
 
For my stock de-lidded CPU, changing the battery does not help either.
Every time I plug/remove RAM, hard disk or Memory checketc, CPU A would disappear.
I had to leave it there power unplugged for a day. Do the SMC thingie to get the CPU detected again.
Strange behaviour.

Just an update for anyone who experienced similar issues.
 
For my stock de-lidded CPU, changing the battery does not help either.
Every time I plug/remove RAM, hard disk or Memory checketc, CPU A would disappear.
I had to leave it there power unplugged for a day. Do the SMC thingie to get the CPU detected again.
Strange behaviour.

Just an update for anyone who experienced similar issues.
Disappears? MacOS won't recognise CPU A? Is there a red LED light on the CPU board between the CPU A socket and the RAM sockets?
 
For my stock de-lidded CPU, changing the battery does not help either.
Every time I plug/remove RAM, hard disk or Memory checketc, CPU A would disappear.
I had to leave it there power unplugged for a day. Do the SMC thingie to get the CPU detected again.
Strange behaviour.

Just an update for anyone who experienced similar issues.

Change CPU A and B (A to B, B to A), perhaps the CPU is faulty.
 
Disappears? MacOS won't recognise CPU A? Is there a red LED light on the CPU board between the CPU A socket and the RAM sockets?
The CPU A is recognized apparently as it shows up as 2 x 2.93GHz Quad Core Intel Xeon CPU, just with the missing CPU A Tdiode, Heatsink, Core 0.
Furthermore, there is no red light or whatsoever on the CPU and backplane board.
[doublepost=1523583696][/doublepost]
Change CPU A and B (A to B, B to A), perhaps the CPU is faulty.
Done that before. Apparently, the CPU is not the faulty one.
[doublepost=1523583798][/doublepost]
Final results, both CPU's, harddrives, and ram sticks are all back in place. Seems to work perfectly..

So, to sum op, seems like a new battery on the motherboard is all it takes. I had the power unplugged.

Does your old missing sensor problem re-occur?
 
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