MP 1,1-5,1 Mac Pro 5,1 can similar ram sticks work for triple channel memory?

[Tommydj10]

I have a dual CPU 2009 Mac Pro 4,1 flashed to 5,1 latest 144 update with upgraded CPUs. I have 4 sticks of 16GB HP ECC RAM part number: 647563-081 (tested and running). I would like to purchase 2 more so I can combine them in triple channel mode. I found on eBay this very similar 16GB modules part number: 628974-081. They both look having the same specs on paper: 1333mhz PC3-10600R Cl9 ECC Registered Dual Rank. Will they work together seamlessly, will they work but not at full performance, or won’t they work at all?

Here’s a link for the first one: eBay ram 1
Here’s a link for the second : eBay ram 2

 

[tsialex]

HP is just relabeling the Elpida and Samsung DIMMs - mixing DIMMs from different manufacturers not always work. Try to buy the same DIMMs that you already have.

 

[tsialex]

Almost forgot, using different DIMMs have a detrimental aspect even when work 100%, the MemoryConfig configuration variables inside the NVRAM volume will take even more space for the memory controller setup and SPD cache - a real problem nowadays when every byte inside the NVRAM counts.

 

[Tommydj10]

Almost forgot, using different DIMMs have a detrimental aspect even when work 100%, the MemoryConfig configuration variables inside the NVRAM volume will take even more space for the memory controller setup and SPD cache - a real problem nowadays when every byte inside the NVRAM counts.

So the bottom line is: even if 2 RAM look the same on paper there might be “hidden”/underlying specs that don’t match, and this might give problems or slow down performance. Correct?

 

[tsialex]

So the bottom line is: even if 2 RAM look the same on paper there might be “hidden”/underlying specs that don’t match, and this might give problems or slow down performance. Correct?

Yes, to avoid it, buy exactly the same DIMM as you already have.