• Memory Slots Ecc Disabled Upgradeable Memory Note
• Memory Slots Ecc Disabled Upgradeable Memory Not Found
• Memory Slots Ecc Disabled Upgradeable Memory Now
• Memory Slots Ecc Disabled Upgradeable Memory Not Working

Mac Pro has a 6-channel memory controller that supports 12 memory slots you can use to install up to 1.5TB of memory using 2933MHz DDR4 ECC compliant memory DIMMs. To ensure compatibility, Apple recommends that you use Apple-approved memory. You can purchase Apple-approved memory online from the Apple Store or by visiting an Apple Retail Store or Apple Authorized Reseller.

Memory requirements

When you upgrade the memory in your Mac Pro, it must meet these requirements:

• 2933MHz DDR4 full-length DIMM. Mixing memory speeds is not recommended.
• Error-correcting code (ECC)
• 8GB, 16GB, 32GB, 64GB, or 128GB DIMMs
• Registered (R-DIMM) or Load-Reduced DIMM (LR-DIMM). Do not mix R-DIMMs and LR-DIMMs.
• 288-pin
• Use the same size memory modules across all slots to maximize performance.
• DIMMs with heatsinks are not supported and may damage the DIMM mechanism.

The Mac Pro supports both R-DIMMs and LR-DIMMs, but you can't mix these two memory types. Mixing R-DIMMs and LR-DIMMs will result in a memory error flash of the status indicator light when you turn on your computer.

Memory Slots Ecc Disabled Upgradeable Memory Note

• Im trying to remove the existing 1 GB RAM in 2 slots and install 2 GB modules in each slot for a total of 8 GB. Why aren't these RAM memory modules working? Memory upgrades are.
• On the BIOS there's no mention of ECC enabled or not, but on the spec of my machine it seems my model has ECC ram. So I'm quite confident that my RAM is ECC Wouldn't it be cool to show on the ZFS page 'your system has ECC RAM, enjoy ZFS' or 'Your system doesn't have ECC RAM, if you use ZFS on it you can lose your data!!!'

Model specifications

Configured from Apple, Mac Pro models include the following DIMM types:

• R-DIMMs for configurations up to 192GB (6x32GB).
• LR-DIMMs for configurations of 384GB (6x64GB) or more.

To determine if the system has parity (ECC) RAM simply count the number of black memory chips on each module. Parity and ECC memory modules have a chip-count divisible by three or five.

All memory included with your Mac Pro is 2933MHz. Mac Pro models with 8 core processors operate memory at 2666MHz.

Learn more

I scoured this and other forums and was unabled to find a good way to do this-- until now!

I recently bought a new Dell T110-II server for a super-low-budget standalone test environment. However, painful first-hand experience has taught me that ECC memory is simply non-optional. Creeping corruption of data over the course of many months will serve as a great reminder in the future.

I bought the server and gave it a nice burn-in using Memtest86+. Unfortunately, it reported that ECC was disabled. A bit of digging showed that the current production release of Memtest86+ doesn't support ECC on the T110-II. No worries, there's a beta available that does. Well... sort of. I couldn't get it to enable ECC either. Then I discovered that the ECC MMU is on the CPU rather than the motherboard and the Celeron processor doesn't support ECC (per Intel ARK.) OK, a couple hundred dollars later I have a nice Xeon sitting in there. ECC is going to come on now, right? Nope. Perhaps Memtest86+ is broken? I started looking for a way to confirm that despite what Memtest86+ said, ECC was really enabled.

The virtualization process masks the details of the host memory from the VMs, so they can't tell me much.

The ESXi shell in ESX 5.0 doesn't have dmidecode available, so my usual trick fails there too.

However, the ESXi shell *does* have smbiosDump. This does pretty much what dmidecode does, just without the decode.

Towards the very bottom I found this little gem:

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Physical Memory Array: #43

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Nice! This is also confirmed later on in the per-DIMM entries:

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Memory Device: #44

Location: 'DIMM A2'

Bank: 'BANK 0'

Manufacturer: '019800000000'

Serial: 'CEAD40B'

Asset Tag: '041236'

Part Number: '9965525-026.A00LF'

Memory Array: #43

Error Info: No Error

Form Factor: 0x09 (DIMM)

Type: 0x18 (Other)

Type Detail: 0x4080 (Synchronous)

Data Width: 64 bits (+64 ECC bits)

Size: 8 GB

Speed: 1333 MHz

So if any of you (or perhaps even a future me) need to find out if ECC is working on your CPU/memory/server combination, this should do the trick for you.

Memory Slots Ecc Disabled Upgradeable Memory Not Found

Feel free to comment if you think this method might be misleading in some cases.

Memory Slots Ecc Disabled Upgradeable Memory Now

Thanks,

Memory Slots Ecc Disabled Upgradeable Memory Not Working

-- Steve Bonds