Sign in with
Sign up | Sign in
Your question
Solved

Variable RAM speeds in multiple compute nodes with E5-2609 Intel

Last response: in Memory
Share
December 9, 2013 1:00:21 PM

Many of these questions touch on overclocking - using RAM faster than 1333 Mhz to grab a few performance gains. My question goes the opposite way: I have roughly 130 compute nodes (HP SL230 Gen 8 blades) all equipped with the E5-2609 processor. A group of these nodes have "faster" memory than 1333 Mhz (I believe 1600) and the newest 32 nodes have even faster rated RAM installed.

I want all of these nodes to be as close as possible for scientific computing purposes. That being said, the current Max Memory Bus Frequency BIOS setting is set to "auto" by default. Does that mean that it will detect the processor bus speed and default down to 1333 Mhz or is it possible that I'm squeaking a bit more out of different mother boards, based on the RAM installed?

What would happen if I select the "1333" setting from the drop-down and hard code that into BIOS?
a c 105 } Memory
December 9, 2013 1:04:13 PM

You're simply squeezing a bit more memory bandwidth out of some nodes compared to others.

If you set them all to 1333 then they would all run at 1333, but the timings may be different.
December 9, 2013 1:51:14 PM

Pinhedd said:
You're simply squeezing a bit more memory bandwidth out of some nodes compared to others.

If you set them all to 1333 then they would all run at 1333, but the timings may be different.


In what way would the timings be different? Would it be better to have all 130 nodes set to "auto" and let the CPU manage things?

The end goal, for this particular group, is to have all nodes as close as possible when it comes to performance. They are running on all of these nodes using a mathematics algorithm and there's a contest which determines code performance based on run time. I've been asked for optimal BIOS settings so that all nodes are as close to the same setting as possible, even if RAM is slightly different.

Best solution

a c 105 } Memory
December 9, 2013 2:20:38 PM
Share

ChrisHP said:
Pinhedd said:
You're simply squeezing a bit more memory bandwidth out of some nodes compared to others.

If you set them all to 1333 then they would all run at 1333, but the timings may be different.


In what way would the timings be different? Would it be better to have all 130 nodes set to "auto" and let the CPU manage things?

The end goal, for this particular group, is to have all nodes as close as possible when it comes to performance. They are running on all of these nodes using a mathematics algorithm and there's a contest which determines code performance based on run time. I've been asked for optimal BIOS settings so that all nodes are as close to the same setting as possible, even if RAM is slightly different.


Yeah in that case just set the DRAM speed rating to DDR3-1333 in the firmware settings. The timings may be marginally different (IE, DDR3-1333G vs DDR3-1333H) but the performance should be extremely close
!