My upgraded Mac Pro 5,1 is dropping RAM modules sometimes

Question

My upgraded Mac Pro 5,1 is dropping RAM modules sometimes

I have a Mac Pro 5,1 Mid 2010 Running Mac OS High Sierra 10.13.6

I upgraded it from a 2.8 GHz Quad Core Xeon to a 3.46 GHz 6 Core Intel Xeon

I also upgraded from 16 GB ram (2x8) to 32 GB (2x16)

The processor upgrade enabled my new ram to run at 1333 MHz

I had no idea that would even happen. OWC explained that it was in fact a thing and that the RAM

that I bought would have run at 1066 under the old processor, but would now run at 1333 under the new one. Nice!

Anyway, the system ran without issue for months

Then I decided to replace the stock ATI Radeon HD 5770 with a Saphire Radeon Pulse RX580 so that I could run Mojave. I upgraded to Mojave and everything was fine. I was driving an LG34GK950F and a

LG34WK95U with no issues, save the lack of a boot screen. But the mac was humming along.

I then realized that I could max out the RAM with another 16 Gig Module. All from OWC. So I did and things continued to run fine.

Somewhere around the 10.14.4 to 10.14.6 update things went south. I'm not saying it was the OS update, but I do recall not having any problems while I was in 10.14.4 and then one day I booted up both my Mac Book Pro (2012) and my Mac Pro and they had both crashed hard. After several hours of recovery drive boots and thumb drive utility repairs, zapping the PRAM and that whole bit... and having to put the original ATI Radeon HD 5770 back in the Mac Pro, I was able to get my systems back up and running.

The Mac Book Pro appears to have needed a new drive. A fresh SSD with a clean install of Mojave and all is well. That is now running 10.14.6 with no issues.

The Mac Pro is running stable again with a time machine restore of High Sierra 10.13.6 and the original ATI Radeon HD 5770, which is able to push the 2 LG 34 inch monitors at 3440x1440 @ 60Hz. If I push the LG34WK95U to 3840x2160 it drops to 30Hz which is horrible. Both are connected via mini DP to DP.

The Saphire Radeon Pulse was sent to Althon Micro to be checked out. I'm hoping I can get that back into the mix at some point. If I can get that back and working my only issue will be that my Ram module in slot 2 keeps randomly disappearing. Sometimes a restart will bring it back. Sometimes it drops out while the system is running.

The single module I bought to max everything out hasn't had a problem. But it was the 2x16 set that had issues. Before I sent the 2x16 GB set back to OWC I moved the RAM around and the red light on the motherboard near the RAM slots followed one of the Modules. I assumed that I had a bad module and OWC agreed. They replaced both modules in that set, which apparently is the thing to do, and now the new modules do the exact same thing. I haven't tried moving them around to see if the red light follows one of them yet.

Another note which may mean something to some of you is that I somehow managed to get my Mac Pro 5,1 to Mojave the first time around without having to upgrade the boot ROM to MP51.0089.B00. I believe it was at MP51.0087.B00 the whole time leading up to the crash that forced me back to 10.13.6

In the process of restoring my 10.13.6 system which involved a recovery mode reinstall of 10.13.6 and some Time Machine work, I was prompted to update the firmware to MP51.0089.B00 and that's where I am at now.

I would very much appreciate the communities thoughts on this. I've scanned other posts but wasn't seeing anything that made sense. If you know of similar issues in other posts I would also appreciate being redirected to those.

Thanks.

Mac Pro, macOS 10.13

Posted on Oct 26, 2019 9:55 AM

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Answer 1

Geotrax

Level 3

568 points

Oct 28, 2019 12:16 PM in response to Eric Strausser

Hello Eric!

Just to be safe, you should probably swap around the RAM modules around and see if the same light turns on, or a different light that follows the "bad" ram stick turns on.

If the light is FOLLOWING a singular RAM stick- there is a chance, although very slim, that you simply have gotten unlucky twice in a row. However, I would recommend cleaning the contacts on the stick before giving up on it entirely.

If the light STAYS in the same slot, then there could be a whole other plethora of possible issues:

The slot could be dirty, and you could possibly fix this with a can of compressed air.
The CPU could be seated improperly, or there could be a piece of debris in the socket (dirt, old thermal paste, etc.) that is causing incorrect contact and the same slot to drop out consistently.
The slot could be physically damaged, which may be game over for that specific slot.
etc.

My first steps would be swapping the faulty module with another module and seeing what happens.

I hope this helps!

-Geotrax

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Answer 2

Nov 15, 2019 11:57 AM in response to Eric Strausser

The second set of replacement ram worked. I first tried to use one of the new modules to replace the bad one from the first replacement set but I was having the same problems. Then I just wholesale swapped out the first replacement set with the second replacement set and all is fine. From speaking with OWC I've gathered that the RAM's official speed is 1066, but the upgraded 3.46 GHz 6 Core Intel Xeon is overclocking them to 1333. But from what I've gathered watching LTT on youtube is that not all units handle overclocking the same. In the PC world I could overclock the CPU, RAM and GPU and make adjustments along the way to push each to their max "stable" speed. But there are no such controls in my Mac. So it either works or fails.. or works for a while and maybe fails. The original set worked for a while and later failed. The second set straight up failed and now the 3rd set has been working for 2 weeks... and hopefully will continue to.

The Saphire Radeon Pulse RX 580 came back from Althon Micro and works now. Odd thing is that the Dual bios switch is missing from the replacement. I asked them about it and they said "The pulse version of this card only carries one bios, some cards were manufacture and Taiwan because of the tariff issue, so they were built with version that carries dual bios switch, but the dual bios on the card were the same bios for both switch position, so for your card, the same bios will work in both PC and Mac Pro. So not to worry, the board might be missing the bios switch but the bios version is the same, same bios will work with both OS system." Normally I would push the issue. The card does come with literature that states that one Bios is tweaked for gaming and the other is tweaked for compute. So.. not sure what to do there. What if I want to sell it? Tempted to just let this one go. Anyway, everything is working right now.

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Answer 3

Oct 31, 2019 4:36 PM in response to Geotrax

Hey Geotrax,

I did moved the RAM modules around and the red light follows one particular RAM module. I went so far as to install them 1 at a time and the problem RAM doesn't even boot the system. The power light on the front of the Mac Pro just flashes. So I'm pretty sure it's gotta be a bad module. Odd thing is that OWC said that the RAM I initially returned had no issues on their Mac Pro test machine. So that's a head scratcher. I'm going to request a replacement of just this one module this time, rather than replacing the 2 that I bought together.

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Answer 4

Oct 26, 2019 10:47 AM in response to Grant Bennet-Alder

Thanks for the link Grant. Lots of good new info in there for me. But now I'm wondering what are the odds that I would get bad RAM modules sent to me twice by OWC. I should check with them and see what they found when they looked at the RAM I have already sent back to them. Would be an interesting jumping off point if it turns out that it was in fact bad RAM, and that it happened two times in a row.

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Answer 5

Oct 26, 2019 10:14 AM in response to Eric Strausser

<<my Ram module in slot 2 keeps randomly disappearing. Sometimes a restart will bring it back. >>

User Tip: Mac Pro and Error Correcting Co… - Apple Community

.

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Answer 6

Geotrax

Level 3

568 points

Nov 18, 2019 11:32 AM in response to Eric Strausser

Eric, I'm happy to hear that everything is working. If you're adamant about a Dual BIOS, you could sell your current card, but the loss you'd take on buying a new one is not worth it in my opinion. Underneath it all the card is still the same, and It should preform just fine.

Honestly, I'd just keep your current setup, since its working fine. Be sure to let us know if you have any other questions!

-Geotrax

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My upgraded Mac Pro 5,1 is dropping RAM modules sometimes

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