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cMP 4,1 Northbridge temp HIGH

adam9c1

adam9c1

macrumors 68000
Original poster
May 2, 2012
1,898
315
Chicagoland
I have had this cMP 4,1 for about 3 years.

Installed Temperature Gauge Pro today
The Northbridge Core temp is in RED at 112*C while the heatsink is around 45*C

I have manually running fans
PCI 36xx
Exhaust 23xx
PS 8xx
Intake 14xx

I have the Core down to 94*C and heatsink to 35*C
Logic Board Ambient is 28*C

UPDATE:
PCI 1800
Exhaust 23xx
PS 8xx
Intake 25xx

Northbridge Core 90*C
Northbridge Heatsink 32*C

Please help.
When I purchased this machine I found a small plastic stand off broken off. I contacted the seller and he told me he replaced some part with a metal screw and thus this must have been leftovers he did not find.
 
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My guess would be this rivet failed, and the seller replace it by a screw.

And now, may be the screw is not tighten anymore, or the thermal paste is dried. There is a reason the original parts is not a simple screw. For short terms repair, you may simply remove the CPU heatsink, un-screw the rivet, replace the thermal paste, and then put the screw back again. But for long term, you may try to get a rivet and replace the screw again.
 
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I'm not comfortable doing this (removing the CPU heatsink).

What can I expect a shop to charge me to replace the clips and put new paste?
 
I have a quote from a local guy that does CPU upgrades on CL and eBay and sells upgrade service, trays, or entire units and he quoted me $500 to fix my tray or $500 + $450 for a replacement tray.

Anything else?
 
adam9c1 said:
I have a quote from a local guy that does CPU upgrades on CL and eBay and sells upgrade service, trays, or entire units and he quoted me $500 to fix my tray or $500 + $450 for a replacement tray.

Anything else?
Click to expand...

You can also try checking out and inquiring from another source, Thomas Pindelski HERE He replaces the Northbridge plastic screws with metal ones for a service fee.
 
$500? My 4,1's CPU tray was faulty few months ago. I took it to the Apple store, they order all the parts (GPU, CPU, mobo, RAM, etc.), checked everything, replaced the CPU tray (to fix the primary problem), clean all the dust, gave my 4,1 a 3 months warranty, and a little report about the stock GPU also partly faulty (also recommend me to get a 3rd party card which is cheaper and more powerful)... And they only charge me $300.
 
+1 to trying the apple shop if you dont want to DIY it.
ask about the price when you drop it off. last time i got a phone call, told the problem, price and ETA on pick up (parts had to be ordered if there in shop it can be same day if your lucky).
if the price they quote is to high you can just go and pick it back up without a charge (at least when iv done it in the uk, assume it's not changed since i last had to go)

ps
the links h9826790 seem to help a lot, sounds like not too hard a job (but if you can afford to get apple to do it id let them as long as they dont want a new CPU tray for a fat price)
https://forums.macrumors.com/thread...at-sink-on-2009-mac-pro-2x2-26.1637891/page-2
 
Took it to Apple Store.
It has failed the bench diag.
They will keep it in store over night for further testing.
I should hear tomorrow or Monday cost of repair..
 
UPDATE:
Apple states the CPU tray is defective. Replacement cost is $300 + tax.
90 day warranty (I imagine the board only).
Apple keeps the old board.
 
They can't just fix the northbridge rivet, but replace the whole module, that's why it cost $300. It's still cheaper than $500, but not as cheap as try to fix it by yourself.
 
I would have tried in my own except for the fact I'm not comfy removing the CPU heat sink. I would have tried if the NB was on its own / not hidden.
 
Remove / install the CPU heatsink is a very very simple job.

I am not computer expert. And I did that quite a few times already. On a single CPU 4,1, if you have no plan to remove the CPU but just the heatsink, there is almost nothing can go wrong.

Even though you really accidentally damage the CPU tray by removing the heatsink. Apple will still only charge you $300 to fix it, not more than that.
 
Yes, it's a bit difference on dual. When you remove the heatsink, you will pull out the CPU as well. So you have to be more careful not to damage the socket, but again, the same $300 if you really damage it.

Here are the possibilities.

1) Fix it by myself, and it's fixed by just $10.

2) Fix it by myself, and doesn't work. Take it to Apple, $300 to replace the CPU tray.

3) Fix it by myself, and I screw up, damage the north bridge, north bridge heatsink, both CPU socket... Take it to Apple, $300 to replace the tray.

4) Fix it by myself, And I screw up, damage the CPU, RAM, heatsink....This will cost me a lot more than $300.

5) Don't even try, and $300 for Apple to replace the tray.

The only option which cost more (in term of money, but not time) is scenario 4. And TBO, it's not that easy to damage those stuff (assume you will do it carefully and slowly). The cMP is a nice designed machine, those worker in Apple is no more than ordinary people. Remove / install CPU heatsink need no more than some normal standard tool. If they can do it, you can do it.

IMO, it's worth to try (and learn) and know more about your machine. Especially you are ready to pay that $300, then why not take the risk? And treat that $300 as the backup plan.

Of course, this is just me. If you are super uncomfortable to do that, better let Apple to do it. Comfortable is priceless, and everyone's value is different.
 
Currently I have 2x 2.66 quads.
What is their power draw and is there a CPU upgrade that does not draw more power?

This unit originally came with two GT120 video adapters (BTO).
I have removed one as every time I had something connected to the second board my displays would blink very often. I took it to Apple Store to diag and they could not find anything wrong. I bought this thinking I would some day run 3rd display. That never happened. Machine has been fine with each single card. But I wonder if my PSU was not up to the task.

I'm slowly debating and trying to fix the NB on my own. And with that it would be perfect time to update processors. I would prefer more cores at lower clock rate even.
 
For more core, you need to do the 5,1 firmware hack, then you can upgrade to dual Hex core.

HOWEVER, the dual 4,1 use lidless CPU. If you want to do the upgrade safely (and easily), you should buy a pair of lidless CPU, which will cost more than normal.

By considering the cost to de-lid the CPU is fixed, get a pair of the top CPU (X5690) is actually make more sense then buy a pair of cheap CPU then pay a lot (relatively) for de-lidding.

For me, it's hard to believe that the PSU is in such bad condition (but still working normally most of the time). It's rated up to 980W, I bet you never use it for more than 50%.

It's very unusual that your CPU can really pull 95W. Even though they do, 95+95+50 (form GT120) = 240W, only 25% PSU loading. Quite a few guys here running dual 130W CPU + much higher TPD GPU, still hasn't reach the limit of the PSU. If only 25% PSU loading can destabilize the system, your PSU must be in very very bad condition. By removing a 50W GT120 shouldn't help anything.

That flickering issue may be software / driver related, not necessary hardware related. Even though it does, may be the GPU itself, may be the port, may be the cable. For such a low TDP GPU and no extra power cable require, it's hard to believe that's PSU related.

In your case, after upgrade to dual X5690 (130W), it's still hard to draw more than 300W. Technically they can draw 130+130+50=310W, however, I doubt if the X5690 in a Mac Pro (without ability to OC) can really draw that much. My W3690 is basically identical to the X5690, which never draw more than 100W (under 100% workload) in my 4,1.

Anyway, if you only want more cores, the X5650 will gives you exactly the same clock speed and TDP, but 2 more cores.
 
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Thanks for the speedy reply.
I could never figure out the issue why the screens would blink out, yet each card worked correctly.
After that I have been running one card with two monitors for a long time, and only recently upgraded to non Apple GT640.

I may revisit the CPU upgrade at a later date.
 
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