Mac Pro 6,1 - 1 RAM DIMM not detected

[djangofan]

I recently bought a refurbished Mac Pro 6,1, with 32GB of ram in all 4 slots. After a month, one of my DIMMs is not being detected, leaving me with only 24GB. Can anyone tell me what approach I should take to troubleshoot this? I am new to Macs (but highly technical) and I am hoping someone out there has experience with this kind of thing?

 

[Slash-2CPU]

Still under warranty? Don't even crack the case. Return it. Anything you do, they may say it's broken because you touched it.

On a hardware level, the 6,1 Mac Pro is an Intel Xeon workstation crammed inside a shiny trash can. It's a strangely-shaped Intel PC. Each slot is its own memory channel back to the CPU.

Three possibilities:
1. DIMM died. Swap DIMMS, see if all DIMMs work.
2. Slot died. Swap DIMMS among slots, see all slots work.
3. CPU isn't making good contact in socket, so one of the memory channels isn't functional. I wouldn't touch that one. Warranty void if you try to access CPU.

 

[alphaod]

Does System Profiler tell you which slot is not detected? Just swap that RAM stick into another working slot and see if it works. Then put a working RAM stick from another slot into the one that is not being detected to see if the slot works.

 

[djangofan]

Ok: here is how I fixed it.

1. My RAM slot #3 was not detected.
2. I opened the case and removed and re-seated slog #3 and rebooted machine
3. After doing that, slot #1 was not not recognized.
4. I opened the case and removed and re-seated ALL 4 DIMMS
5. When I restarted machine it is now fixed and back to normal.

Thanks for your help guys.

 

[pischu12]

That's totally weird right I had a slot go quiet - replaced the CPU board and now all well .... I had switched the RAM around with other know good sticks - and always the same slot would would be "quiet" . Thank god I got a really good deal for the CPU card to be able to fix it . My worry was that it "might" spread.... hence jumping in and fixing it ( besides the fact that mentally it bothered me me lol ) cause 48 G RAM is still perfect 99.5 % of the time.

 

[mikas]

The RAM slotsin 6,1 are unnecessarily fragile. I did damage one slot just putting in some more RAM. Me too bought a new CPU board, but haven't swapped/used it till now. I've got 96GB in that one, and as you say it's enough, me too think it's enough for the use cases of mine today. The extra board, well it's there in reserve though if needed one day.

I own 3 pcs of 6,1's, please don't ask why .

 

[pischu12]

OMG I thought it was just me owning several - I am so ever guilty as charged lol !!!! Thank god I have "slowly" let go of the addiction of wanting another Thank you for your insight !!!! So very appreciated.

 

[dieter12]

Why does my MacPro 6.1 not recognice 32GB 4Rx4 PC3 14900L ECC Ram? 64GB works fine.