Memory question - Mixing Memory

[Bill1950]

When using dual CPU systems where each CPU controls "its own" banks of memory, is it necessary to have all identical memory for both CPUs or just for each individual CPU? I am assuming all memory is RDIMM and the same speed, but, for example, maybe one CPU is using Samsung and the other using Micron with slightly different latency.

I am basing my question on what seems to be discrete CPU memory controllers, one on each CPU, where CPU0 doesn't actually see the memory on CPU1.

 

[Patrick]

What processor? With the E5 V1-> V4 I verified it works in Intel platforms we have used.

 

[Bill1950]

E5-2670 V1 on an ASROCK Rack EP2C602-4L/D16. So mixed mem works OK as long as it's all identical on a given CPU?

 

[Patrick]

E5-2670 V1 on an ASROCK Rack EP2C602-4L/D16. So mixed mem works OK as long as it's all identical on a given CPU?

It should work.

 

[Bill1950]

I will order some memory and try it. I'll report back.

 

[wildpig1234]

ranking should be the same throughout. Theres more flexibility with speed and low/regular voltage.

 

[Bill1950]

I have four decades in IT, but not sure what you mean by "ranking."

 

[wildpig1234]

What Are Memory Ranks, Why Do We Have Them and Why Are They Important? | Dataram Blog

 

[Bill1950]

My intent is to use 8 matching memory sticks on each CPU. The memory on one CPU will probably NOT be identical to the other.

 

[NetWise]

If you have 8 and 8 matching why not make it two sets of 4 on each CPU and avoid the issue?


Sent from my iPhone using Tapatalk

 

[Bill1950]

I am currently using 4 x 4gb on each of the CPUs. I want to move all the existing matching memory to one of the CPUs giving it 8 x 4gb. Then I'd like to acquire another 8 x 4gb to put on the second CPU. Getting to 64gb memory that way is less expensive than picking up two sets of 4 x 8gb memory. Not sure if it makes any performance difference one way or t'other.

Forgot to mention that I might not be able to get the same kind of Samsung memory as I currently am using.

 

[herby]

I am currently using 4 x 4gb on each of the CPUs. I want to move all the existing matching memory to one of the CPUs giving it 8 x 4gb. Then I'd like to acquire another 8 x 4gb to put on the second CPU. Getting to 64gb memory that way is less expensive than picking up two sets of 4 x 8gb memory. Not sure if it makes any performance difference one way or t'other.

Forgot to mention that I might not be able to get the same kind of Samsung memory as I currently am using.

It could make a difference in performance depending on the rank of the DIMMs. I know maxing out the slots on my AMD Supermicro boards will limit the frequency of dual or quad rank DDR3 DIMMs. Check the manual for your board, it probably has a chart showing how much you stand to lose.