Fan issues after CPU replacement

[nrogers85]

Hello all, and thanks in advance for any help you can offer. I’ve recently upgraded a 2009 4,1 to a flashed 5,1.

Specs are:
128gb 1333mhz ram
Dual X3680 (delidded)
OS: 10.12.6
GPU: Flashed MSI Radeon 7590 3gb
Boot drive: 250gb SATA Samsung 860 evo on PCIe blade
Additional drives: Three 2tb HDDs (one in optical slot, 2 in drive bays), Samsung evo 840 250gb ssd running Mavericks (for the occasional use of legacy software)


My question is this, after the upgrade the system seems to be stable. As in, no random shut offs or reboots. However, with only a minimal load the fans go nuts.

I’m an audio engineer, using Pro Tools 12.5.2. The system was stable with the previous CPU tray (a single quad tray that I upgraded to a single hex), but was maxing out under heavy load. Even then the fans would not soar as high as they do now. Macs Fan control reads 98 degrees Celsius on CPU A with only a 14% load and the fans kick in to overdrive. The heat sink temp is around 60, while CPU B stays extremely low by comparison. Could this be a result of improper thermal compound or improper tightening on the heat sink?

Thanks!

 

[flowrider]

Have a feeling that the dual CPU tray you exchanged for the single CPU tray, is from a real cMP 5,1. These trays are not interchangeable between the 4,1 and 5,1 cMPs. If a tray from a real 5,1 is installed in a 4,1 (even one upgraded with 5,1 firmware), the fans will rev up to full speed exactly as you are describing. There is no fix for this, other than using the correct tray.

Lou

 

[nrogers85]

I doubt this, as I tested the tray with the original dual quad processors with no issue. Ran stress tests, including opening the same Pro tools system the machine goes wild at now. Only upon cpu upgrade did the issue arise. Thank you kindly for your input though. I did make quite sure that the SMC and boot rom were the same. It’s my understanding that the system would ramp up the fans even under no load if it were a 5,1 tray .I can browse comfortably, do menial tasks, but throw anything even mildly taxing at it and the fan system goes wild.

Have a feeling that the dual CPU tray you exchanged for the single CPU tray, is from a real cMP 5,1. These trays are not interchangeable between the 4,1 and 5,1 cMPs. If a tray from a real 5,1 is installed in a 4,1 (even one upgraded with 5,1 firmware), the fans will rev up to full speed exactly as you are describing. There is no fix for this, other than using the correct tray.

Lou

 

[Macschrauber]

Have you zapped the Pram ?

 

[nrogers85]

Excuse my incomplete OP, I should have mentioned that I have done the PRAM (with multiple configurations in both dual and triple channel, in small amounts and large to rule out any specific dimm issues) as well as mutiple SMC resets, both in a bare bones configuration and with peripherals attached, eliminating each one by one.

Have you zapped the Pram ?

 

[w1z]

90C is high for a 13% workload. Switch the CPUs around, reapply the thermal paste and double check your heatsink installation.

If the issue persists but with CPU B this time then you have a faulty CPU.

 

[flowrider]

If it's a 4,1 tray you would need to do some modifications on the CPUs or the mounting method for the lidded CPUs vs the non-lidded CPUs that the 4,1 uses. Question - How were the new CPUs installed?

Lou

 

[h9826790]

Remove the plastic retainer if you didn't clear ALL the silicon seal on the delidded CPU.

The silicon seal will lift the plastic retainer a bit, which cause the heatsink unable to "touch" the CPU". So that, high temperature on the CPU, and low temperature on the heatsink, and all fans go nuts (because of overheating).

 

[MVMNT]

Definitely worth cleaning and reseating the CPUs first. Swap them over as a split test but keep the same rotations when untightening and tightening the screws.

Check for any debris under the CPUs or the heat sink connectors also. Small debris can throw off the sensors but still allow for “normal” operation. Check the sensors themselves too.

 

[nrogers85]

That sounds very reasonable. I hadn’t considered that. I did use the plastic retainer, and did not remove the seal on the chip. I will remove the retainer and report back. Thanks everyone!

Remove the plastic retainer if you didn't clear ALL the silicon seal on the delidded CPU.

The silicon seal will lift the plastic retainer a bit, which cause the heatsink unable to "touch" the CPU". So that, high temperature on the CPU, and low temperature on the heatsink, and all fans go nuts (because of overheating).

 

[nrogers85]

PRAM reset multiple times with different ram configurations, smc reset numerous times.

Have you zapped the Pram ?

 

[nrogers85]

I’m in the early stages of testing after removing the plastic retainer, reapplying thermal paste and reseating the heat sink. So far so good! The same session that was a 14% load and causing 98 degree cpu temps is now operating fine. Fans are spinning very lightly above minimum, and cpu a diode reads around 60 with the heat sink around the same temp. I am in your debt! It makes total sense that your solution worked, and never occurred to me in the original installation process. It never appeared in any of the literature I referenced either. My hat is off to you, thank you!

Remove the plastic retainer if you didn't clear ALL the silicon seal on the delidded CPU.

The silicon seal will lift the plastic retainer a bit, which cause the heatsink unable to "touch" the CPU". So that, high temperature on the CPU, and low temperature on the heatsink, and all fans go nuts (because of overheating).