MP 1,1-5,1 2012 Mac Pro 5,1 CPU upgrade ram slot 1 not recognized

[Dial430]

I need a little help troubleshooting my cpu upgrade. I have a 2012 Mac Pro 5,1 with dual 2.4 GHz processors and 6 modules of 16 GB ram which I recently installed. All the ram was recognized and slots 1 to 6. I upgraded the cpu to dual 3.46 GHz processors. When I first booted up the computer came and both cpus were seen, but slot 1, 4, 8 where not recognized. The System information said 5 slots where being used and 3 were empty. When the computer booted up, the red light between the processors came on. I know this means that one or more slots are not being recognized as I had a "dead" module when I first upgraded the ram. I shutdown, removed both heat sinks, cleaned the Arctic 5 paste, inspected both cpu. Undermagification, I could not see anything in either socket or cpu. I replaced, re pasted and restarted. I "thought" I had switched cpus to see if it was one of them, but I wasn't positive, because the first time I did the install, I thought maybe the heats sinks weren't tight, not enough paste, who knows? But on the second reboot, the same result, both cpus recognized, but System Information says 5 slots occupied and 3 slots open, slots 1, 4 and 8. So I shut down, and repeat the install for the third time. Thoroughly inspected both cpus, sockets, reinstalled, now I'm out of Arctic 5 so whatever solution, if it requires another install of both cpus will have to wait. Third boot, same result, 5 slots each with 16GB ram, in 2,3, 5,6,7. System Information says 5 slots seen, the red light on the board light up at reboot, each of the three times I have booted. Did my logic board take this time to died, or get sick at slot 1?
I ran a Geekbench 5 CPU test and got 643 single core and 5339 multi core which I think is really bad for the 3.46GHZ cpu, right? So maybe bad cpus, from Ebay?

 

[Macschrauber]

check cpu sockets for bent pins

clean the prozessor pads with isopropyl

on a real 5.1 cpu board heat sink pressure is not relevant for the memory controller inside the xeons.

maybe Firmware memoryconfigs are expanding.

try 4 nvram resets in one row to reread spd data and rebuilt memoryconfigs inside the 1st store.

if you can, save a rom dump. Google dosdude romtool for the tool.

 

[Dial430]

check cpu sockets for bent pins

clean the prozessor pads with isopropyl

on a real 5.1 cpu board heat sink pressure is not relevant for the memory controller inside the xeons.

maybe Firmware memoryconfigs are expanding.

try 4 nvram resets in one row to reread spd data and rebuilt memoryconfigs inside the 1st store.

if you can, save a rom dump. Google dosdude romtool for the tool.

Thanks for the suggestions. On the second and third re-installs I closely inspected both sockets and both cpus under 2 2.5 magnification viewer and did not see anything that looked out of place, bent etc. I completely cleaned both cpus and coolers, I used both 90% isopropyl alcohol and Arctic Silver #2 cleaner, reapplied thermal paste the same on both cpus, each time and I have switched the cpus and still the first slot is no go. I tried booting with only 1 module in slot 1. The red light did not go on and neither did the mac boot. Nothing. So I shutdown and then did a NVRAM reset, 4 times, with 4 modules in the first two slots in each ram bank. Red light, boots but no joy, slot 1 not seen. I go get the romtool, and do what with it? Not sure what memoryconfigs expanding means? Downloaded Romtool, but password protected for opening info.plist?

 

[Dial430]

I forgot to mention that I have my ssd and my nvme boot drives using Opencore 6.2, not sure if that should affect the memory slot 1??

 

[Dial430]

One more data point. I put all 6 16GB ram modules in slots 2,3,4 and 5,6 7. Mac booted fine, no red light, System reported all 96GB, with slot 1 and 8 empty.??

 

[phycofrantic]

I have same machine with exact same issue I gave up and just accepted 96 gb lol this decision had a few other factors going into it.

1. from my exp unless something wrong with my machine I found through trail and error that with 3 or 6 modules the memory would run in 1333Mhz triple channel mode as opposed to with 4 they would not run in triple channel and slow down to 1066Mhz

2. The 96 GB no matter what I have tried (and I have tried hard) has ever been saturated further than 1/3 - 1/2 actually being used thus 128 GB being beyond overkill imo

 

[Dial430]

The 96 GB is running at 1333 MHz. The system seems to be running OK. I ran Geekbench 2,3 and 5, 32 and 64bit and the scores seem to be a big improvement over my 2.4GHz cpus. Not a sure what I was expecting with the upgrade to 3.46, but it is faster, I seem to be using all the installed memory, so as long as I don’t look in and see the empty slot 1, I think I’ll just let it go. Installing and reinstalling the two cpus three times was enough excitement for 1 year.

 

[phycofrantic]

download macfancontrol if you haven't already and monitor temps the dual cpu northbridge tends to run high due to a faulty spring (someone feel free to correct if wrong) You can buy like a $10-15 kit to replace it or I just increase fan speeds slightly to attempt to keep it under control for longevity

 

[Macschrauber]

you can also inspect ram slot 1, got one machine there was a piece of thermal paste in the slot.

 

[Dial430]

Thanks for the suggestions. I will reinspect slot 1. I am running TG pro to monitor temps and running fans st 25%. Temps seem okay, in the 35-45°C range for the cpus and maybe 45- 60° for Northbridge, but cpu A is running hotter at the high end of the range. I did replace the pins on Northbridge first, it was difficult to get the pins in and secure to the board so the paste possibly could be re-done with better technique.

 

[Macschrauber]

Post a screenshot of the temperatures in celsius people here are really good interpreting the temps.

 

[Dial430]

I have attached a screenshot of the TG Pro temps. The temps are all running in the 35 to 50C range.

 

[Macschrauber]

If you need to take it apart again, take a closer look at Northbridge, this seems to be a little high delta.

Keep watching Northbridge, temperatures should not spread wider than yet. NB can run hotter but the delta between chip and heatsink should not rise.

 

[LouCioccio]

I want to add my 2¢ I have a 2010 Mac Pro that had a single CPU and did buy a dual off eBay of one that CPU B did not work after the fellow had repasted and upgraded the CPU's. He would accept an offer and he had images of the CPU sockets and nothing stood out as smashed pins. So I took a chance and figured I'll accept the challenge. I received the the dual CPU sled on the 12 of April 2021. So I took it apart cleaned it up it was not really that dusty or dirty. I decided to take the Northbridge apart and sure enough that paste was dried.But I did look on ways to replace the pins and found two of them. When I ordered the plastic type I did not realize they were coming from China. So as they were on a slow "boat" I decided to do the second one with screws, nylon washers and nut plus drilling a small hole in the sled.
I inspected the the CPU B socket one pin stood out it was askew and I used my Camera inspection of sensor thet has a magnifier and led lights. I was able to adjust it. It seemed no matter how careful I was installing the the heat sync on B it was never quite right. I don't remember the times I tried counting I was doing some thing wrong. The sled would not boot totally as I could hear access to the DVD. No error led I even changed the 2032 battery. Now if I remove the B cpu A would boot up with the fans at full speed like the tech manual says. I even ordered a another CPU in case the one did not work. You put them in socket A they all worked, so back to the pins. I did price out what a replacement socked would cost. Finally I decided to pick up a Toy Video Micro Scope and that really helped as I located 4 pins elsewhere that were not aligned. I was able to tweak them. So I put the heats sync back on but still no boot or any errors. Remove the CPU Heat sync BUT leave the CPU B in if it over heats it will shut down. So I tried just CPU B no heat sync and it booted but shut down before the log on screen. Now this is where gets strange I put the heat sync back on no boot. SO what do I have to loose I loosen each screw a ½ turn install the sled no boot. I am not sure how many times ½ turn loose I did but it booted!! I ran tech tools and even have iStat Northbridge is around 55ºC and the CPU's run around 40ºC I had it running for 5 hours but nothing broke and seems stable I have rebooted several times. I did get the sled with the CPU's for 230$US plus 15$ shipping. I will update later.
--Lou Cioccio--