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User profile for user: acphot
acphot Author
User level: Level 1
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Mac Pro 5.1 Early 2009 Upgraded 2 x 3.06 GHz 6-Core - PC3 or PC3L memory?

Hi everyone,


I have an early 2009 Mac Pro which is upgraded to 5.1

It has a 2 x 3.06 GHz 6 Core tray (12 core) - SMC Version 1.39f5


Currently fitted with 32GB - 8 x 4GB sticks (PC3-1600 DDR3 EEC 1333MHz)


I want to upgrade it to 64GB - 8 x 8GB sticks (PC3-1600 DDR3 EEC 1333MHz)


My question is - Does it have to be PC3 or is PC3L okay?


Reason I ask is that it seems more available and cheaper for the PC3L, but I don't want to compromise on speed?


Thanks for any advise?

Mac Pro, OS X 10.11

Posted on Feb 16, 2023 7:31 AM

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User profile for user: Grant Bennet-Alder
Grant Bennet-Alder
User level: Level 10
127,879 points

Posted on Feb 16, 2023 10:48 AM

You can spend a month or so studying the many, many, many issue about memory parameters, or...


...you can buy from a company that is already an expert, and sells memory that:


It works in your Mac,

or your money back.


your Mac Pro uses 72-bits wide Errors Correcting Code memory.




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User profile for user: acphot
acphot Author
User level: Level 1
17 points

Feb 22, 2023 4:49 AM in response to acphot

Hi, thanks everyone for all the info.


All help received has led me to this on Amazon.

'OWC - 64GB OWC Memory Upgrade Kit - 4 x 16GB PC10600 DDR3 ECC-R 1333MHz DIMMs for Mac Pro 2009-2012 'Nehalem' & 'Westmere' models'

This is from Amazon USA, (Amazon.com) I am in UK but I can buy import.


It appears to be what I am after to upgrade to 64GB using all four slots 4x16GB but....


It is not PC3L as per my original question. It is PC3

However it is ECC-R rather than just ECC. I am not really sure what the '-R' is, if anyone can enlighten me?

From what I can see it just means that I can only use these sticks and they will not mix with other brands.


The listing on Amazon is a bit confusing as it states that it is compatible with my 'Mac Pro 6-Core (Mid 2010-2012) (July, 2010 / June 2012) Model ID: MacPro5,1 (3.33GHz)' in one sentence but lower down in the description it further states 'This kit is compatible with dual processor (8-core & 12-core) Mac Pro models ONLY. While single processor (Quad and 6-core) Mac Pro models do have 4 memory slots available, This kit is not compatible due to an OS system limitation'


So all still very confused as to will it work or not?




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User profile for user: Grant Bennet-Alder
Grant Bennet-Alder
User level: Level 10
127,879 points

Feb 22, 2023 5:31 AM in response to acphot

if you had a single Quad core, NO.

if you had a single Hexacore, NO.

Four modules like these work only in the two-chip models like the 12-core, and can not be mixed (on a side) with smaller modules.


Mac Pro ECC DIMMs larger than 8GB have so many devices on board that the standard way of just connecting their outputs together overwhelms the driving abilities of the chips outputs and they don't work properly. So for 16GB and larger, an output Register is added to each DIMM to drive the output data onto the system Bus.


This stronger output Register overwhelms the outputs of any remaining smaller modules, so they stop working. For this reason, on each side, you need to choose Registered DIMMS like these, or un-Registered DIMMs like almost all smaller modules.

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User profile for user: acphot
acphot Author
User level: Level 1
17 points

Feb 22, 2023 6:03 AM in response to Grant Bennet-Alder

Hi, thanks for the reply.


I realise that I should have updated my original question regarding my 12 core 2 x 3.06 upgrading to 64GB.

I have now upgraded this computer to 64GB using 8 x SAMSUNG M393B1K70DH0-CH9Q8 HP 500205 PC3-10600R DDR3-1333 Server RAM

The computer all appears to be working fine with these 8GB sticks and I am happy with 64GB.


I am now looking to upgrade my Mac Pro 5.1 Mid 2010 6 core 1 x 3.33

It currently uses all 4 slots 4 x 8GB (32GB)


Is it possible to upgrade this to 4 x 16GB (64GB) or as I've seen elsewhere the max for the 6 core single processor is 48GB, using 3 slots (3 x 16GB) leaving last slot empty?


Thanks.

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User profile for user: Grant Bennet-Alder
Grant Bennet-Alder
User level: Level 10
127,879 points

Feb 22, 2023 7:03 AM in response to acphot

They tried to tell you in simple terms that for the one chip quad core and hexacore you can only reliably use three of the four slots at this size modules.


I tried to explain above that if you install ANY 16 GB or larger DIMM on a side, all the Un-Registered modules MUST be removed.


Don't pay to ship memories from the US to the UK.

OWC has a Distributor and Dealers in the UK:


https://www.owc.com/partners/where-to-buy#map

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Mac Pro 5.1 Early 2009 Upgraded 2 x 3.06 GHz 6-Core - PC3 or PC3L memory?

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