MP 1,1-5,1 High CPU fan idle speeds.

[Avalon74]

Recently my 4,1>5,1 cMP has been experiencing some odd behavior. My CPU fans will start out at 1100RPM before slowly starting to ramp up in intensity.

This picture is after 5 or so minutes of the system being on:

The system is otherwise at idle. It appears that this is tied to the Northbridge temperature, which starts out at ~50 =C and then slowly tries to climb past 80C. I just recently put new thermal paste on the northbridge and new clips, because it had been running at 90C at one point.

Just in typing this post the CPU fans have gone from 1600RPM in the screen shot above to over 2100RPM in less than 5 minutes. (Though the northbridge is now at 78C).

Im quite confused and dont know how to solve this issue.

 

[Macschrauber]

Check out activity monitor, something is loading the CPUs

 

[tsialex]

Recently my 4,1>5,1 cMP has been experiencing some odd behavior. My CPU fans will start out at 1100RPM before slowly starting to ramp up in intensity.

This picture is after 5 or so minutes of the system being on:

The system is otherwise at idle. It appears that this is tied to the Northbridge temperature, which starts out at ~50 =C and then slowly tries to climb past 80C. I just recently put new thermal paste on the northbridge and new clips, because it had been running at 90C at one point.

Just in typing this post the CPU fans have gone from 1600RPM in the screen shot above to over 2100RPM in less than 5 minutes. (Though the northbridge is now at 78C).

Im quite confused and dont know how to solve this issue.

Your ~13ºC delta between the northbridge heatsink and the northbridge internal diode is very suspicious, something is wrong.

Maybe your heatsink is not installed correctly or your northbridge became concave/convex after the cooking.

 

[Avalon74]

Check out activity monitor, something is loading the CPUs

Nothing is loading the CPU with any sort of high load. The idle readout is 99%.

Your ~13ºC delta between the northbridge heatsink and the northbridge internal diode is very suspicious, something is wrong.

Maybe your heatsink is not installed correctly or your northbridge became concave/convex after the cooking.

Im not certain how it could be install incorrectly, Ive used push pins like these which Ive seen suggested before. But assuming that it is installed incorrectly, or that the northbridge is somehow deformed, how could I tell? And more importantly, what is the solution?

 

[tsialex]

Nothing is loading the CPU with any sort of high load. The idle readout is 99%.



Im not certain how it could be install incorrectly, Ive used push pins like these which Ive seen suggested before. But assuming that it is installed incorrectly, or that the northbridge is somehow deformed, how could I tell? And more importantly, what is the solution?

It's not uncommon after superheating of the northbridge that it became out of shape, you can always check if the heatsink, or the northbridge itself, are concave/convex using a rule or, even better, a reference parallel bar.

I used sand paper to correct north bridges before, it's not really difficult to do, but it's a burden to clean the CPU tray after getting it into shape.
[automerge]1595453476[/automerge]
Btw, the original springs are stronger than the normal push pins on the market, maybe it's better to try with the eBay kit that uses stronger springs.

Mac Pro 4,1 and 5,1 Northbridge heatsink retainer spring kit | eBay

This precision spring kit is the definitive answer to repairing your Mac Pro 4,1 and 5,1 Northbridge heat sink broken rivets. Fix your Mac Pro before you have a catastrophic failure like many have already.

www.ebay.com

 

[Avalon74]

It's not uncommon after superheating of the northbridge that it became out of shape, you can always check if the heatsink, or the northbridge itself, are concave/convex using a rule or, even better, a reference parallel bar.

I used sand paper to correct north bridges before, it's not really difficult to do, but it's a burden to clean the CPU tray after getting it into shape.
[automerge]1595453414[/automerge]
Btw, the original springs are stronger than the normal push pins on the market, maybe it's better to try with the eBay kit that uses stronger springs.

Ah, lap the northbridge die. I could do that yes. If I need to any particular grit of sandpaper I should use? (I assume a can of compressed air would also come in handy for cleaning the board?)

I do have an ebay order in for this kit which should allow far better mounting pressure than the pins I currently have, which I do notice allow the heatsink to wiggle slightly (not super loose, but it does move slightly). (Ah... I see you linked me this exact kit... well thats good).

I always suppose my last resort is sourcing a replacement 09 processor board from somewhere... but Id prefer to not have to do that.

 

[tsialex]

Ah, lap the northbridge die. I could do that yes. If I need to any particular grit of sandpaper I should use? (I assume a can of compressed air would also come in handy for cleaning the board?)

I do have an ebay order in for this kit which should allow far better mounting pressure than the pins I currently have, which I do notice allow the heatsink to wiggle slightly (not super loose, but it does move slightly). (Ah... I see you linked me this exact kit... well thats good).

I'd try with the eBay kit first. Even with an air compressor, it's more difficult to clean the tray than to sand the northbridge. No need to really lap it, just to make it parallel again, start with 400 sandpaper for a rough cut removing the concave/convex shape, then go to 800 and 1200 to make the fine cuts.

 

[Avalon74]

I'd try with the eBay kit first. Even with an air compressor, it's more difficult to clean the tray than to sand the northbridge. No need to really lap it, just to make it parallel again, start with 400 sandpaper for a rough cut removing the concave/convex shape, then go to 800 and 1200 to make the fine cuts.

Yes, that is my plan, I'll try with the bolts first and then move on to the slightly more drastic step of sanding the die itself. (Though while I have the heatsink off again I'll check to see if it was deformed by the high temps).

 

[Avalon74]

I'd try with the eBay kit first. Even with an air compressor, it's more difficult to clean the tray than to sand the northbridge. No need to really lap it, just to make it parallel again, start with 400 sandpaper for a rough cut removing the concave/convex shape, then go to 800 and 1200 to make the fine cuts.

Just coming back to this... the spring and bolt kit came today and I just swapped the white push pegs for the bolts and new springs, but the system is exhibiting the same behavior. Been turned on for 5 mins and Im already at 1700RPM on both CPU fans and a 79C Northbridge Diode temperature with a 66C Northbridge heatsink temperature. Checked the levelness of the Northbridge itself when I had it disassembled this time and it seemed level. So Im at a loss here...

 

[KeesMacPro]

@Avalon74 :
It's summer now Temps are higher.
Do you still have all the fans on auto like in post #1 ?
Delta NB heatsink and NB diode is 13 degrees, it' s not perfect but it's not very bad either...

I'd set the intake and Boost A fan depending on the NB diode:
Both fans increasing at 55 degrees and max rpm at 80 degrees , see what happens to the Temps.

Here's a screenshot of mine to compare, it's like 33 degrees here ...

 

[Avalon74]

@Avalon74 :
It's summer now Temps are higher.
Do you still have all the fans on auto like in post #1 ?
Delta NB heatsink and NB diode is 13 degrees, it' s not perfect but it's not very bad either...

I'd set the intake and Boost A fan depending on the NB diode:
Both fans increasing at 55 degrees and max rpm at 80 degrees , see what happens to the Temps.

Here's a screenshot of mine to compare, it's like 33 degrees here ...

Yes everything is still on auto, before this started occurring the system was nearly silent when at idle. Right now the temps have sort of stabilized at 77C for the NB with the fan RPMs at ~2200.

I set the fans as you have them and theyre currently running at 1300 RPM on the intake and 2400 on the BOOSTA fan. NB is sitting at 65C. Case ambient is 36C.

 

[tsialex]

Just coming back to this... the spring and bolt kit came today and I just swapped the white push pegs for the bolts and new springs, but the system is exhibiting the same behavior. Been turned on for 5 mins and Im already at 1700RPM on both CPU fans and a 79C Northbridge Diode temperature with a 66C Northbridge heatsink temperature. Checked the levelness of the Northbridge itself when I had it disassembled this time and it seemed level. So Im at a loss here...

Maybe something else on your tray is now damaged, since with a normally working one should be getting high 60s to low 70s Celsius.

Did you tested you Mac Pro with another CPU tray to see if the same happens again? Another test to do is to install your heatsink with a working tray to check if the sensor is up to specs.

 

[Avalon74]

Maybe something else on your tray is now damaged, since with a normally working one should be getting high 60s to low 70s Celsius.

Did you tested you Mac Pro with another CPU tray to see if the same happens again? Another test to do is to install your heatsink with a working tray to check if the sensor is up to specs.

Unfortunately I do not have a 2nd tray (dual CPU or otherwise) to test with. I have located a few places online that are selling them, so I may have to just bite the bullet and buy one.


EDIT: Just ordered a processor board from MacPalace... Ive heard mixed things about them... so I'll see how this goes, but ebay wants $500+ for a dual CPU tray with CPUs... short of this not working I guess I could always just order a singe CPU tray and use that while I figure out the issues with this dual tray....

EDIT2: MacPalace had the board listed for $240, then emails to say it was actually $595... so thats not gonna happen...

 

[TomMuc]

we have 6 macpro 4.1/5.1 and the 13 degree delta between northbridge diode and heatsink in my eyes does not look too bad. i‘d first try to reset the smc (which is quite an apple miracle). another idea is to boot once with win7 that often has a very calming effect on fan speeds. to read the values in windows you can use eg hwinfo.