MP 1,1-5,1 Advice: not all memory appearing online

[danallen]

Here's my About This Mac. I got this in 2014. No problems, except until today, where it says 56GB 1333 Mhz DDR3, it has always said 64GB 133 Mhz DDR3. If you have any thoughts or advice, I would be grateful for anything you can tell me. Computer is still running. Thank you.

 

[tsialex]

Go to SystemReport/Memory and see if all the 8GB DIMMs are working, then open your Mac Pro and check if any of red LEDs of the CPU tray are lit.

You probably had one DIMM failure.

 

[danallen]

System report

 

[danallen]

Would this stick work for a replacement?

 

[tsialex]

Would this stick work for a replacement?

View attachment 864413

No, OWC is selling a ECC UDIMM memory while yours is a ECC RDIMM, see the Texas Instrument Registered Control Chip at the centre of your Kingston DIMMs. You can't mix-match Unbuffered with Registered memory, only one type of RAM can be used at a time.

 

[danallen]

No, OWC is selling a ECC UDIMM memory while yours is a ECC RDIMM, see the Texas Instrument Registered Control Chip at the centre of your Kingston DIMMs. You can't mix-match Unbuffered with Registered memory, only one type of RAM can be used at a time.

I really appreciate your assistance in identifying the right memory.

I found a few other modules I have reason to believe might work. If you have a moment to let me know anything I should know, I will be extremely grateful. I fully recognize you have no obligation to do this.

I checked with OWS, explaining what you pointed out about the registered vs. unbuffered DIMM. The guy in their chat said he cannot guarantee 100%, but he thinks this slightly different product is likely to work:

This one has the a TI chip in the spot you pointed out on my memory, but the picture is not clear enough to read the lettering. To the extent I can make out the charcters, it looks like a match. However, some of the labeling is different from the one module visible in the picture of the memory in my system. The memory in my system has a variety of labels, so I am not sure how to know what works and what does not.

Next candidate:

This one says 8GB but also says 24GB Equivialent, I don't know what that means.

And another

A few more in next post




In My Computer Now

To clarify what is in my computer now, there are 5 modules that look like this:

The other three in my computer now look like this:

This picture shows the led that is lighting up and marks the slot I am guessing corresponds to that light.

 

[danallen]

More memory that to me looks like it should work, but I am not clear on everything to look for:

This one has the benefit of being new:

Last candidate:

 

[tsialex]

Try to buy the same DIMM that you already have, it’s not a good policy to have dissimilar DIMMs installed, you can have compatibility problems that make your Mac to not boot or boot with memory speed reduced.

Kingston is a difficult brand to buy since it changes a lot, from batch to batch. See what is the module/label that you have more examples and buy it.

Maybe the Micron memory will be a lot easier to buy, see if you still have all working then buy one and use 4 Micron with one CPU, 4 Kingston with the other.

Forget OWC memory.

 

[danallen]

RESOLVED

1. Referred to this url: https://support.apple.com/en-us/HT205043#1 That url includes this diagram:

2. Ran the utility mentioned in that guide, at /System/Library/CoreServices/Memory\ Slot\ Utility.app
3. That utility put up a screen indicating memory slot 5 (that had the dead memory module) should be filled and slot 8 should be left empty.
4. I moved the module from slot 8 to slot 5, leaving slot 8 empty, per the guide.
5. After restart, everything was ok.
6. For kicks, I put the dead module into slot 8.
7. Fixed

I owe you for your time. Thank you for the education.

 

[Macschrauber]

Guess ist was simply the physical removing - plugging of the memory sticks.

A good cleaning of the contacts with isopropyl alcohol would be useful, too.