ML110: Adding DIMM + Memory Interleaving

[RufusG]

I have a new ProLiant ML110G2
(Model# 382050, Pentium 4, 3.2GHz )

It came with a 256MB DIMM installed.

I have discarded that and installed 1 single 1GB DIMM (DDR3200)

If I install a second 1GB DIMM will I achieve better system performance due to memory interleaving ?

Anyone have background reading on this subject ?

Anyone have a chart on which size DIMMs I can mix and match, as the HP telephone support line told me that I cannot mix sizes.

Thanks in advance for your help and advice.

Regards

[Oleg Koroz]

Page 39
http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00302239/c00302239.pdf

[RufusG]

Thank you the pointer to the HP manual, which I had already downloaded.

Is it possible to gain a performance improvement by installing DIMMs in pairs ?
( Memory Interleaving )

The manual is not at all clear about this

Can anyone add any more information on this ?

Thanks

[Terry Hutchings]

According to the quickspecs for this server, "optional interleaving" is an available feature. In all the other Proliant servers interleaving is accomplished just by adding another dimm of exactly the same kind to get a pair.

If the goal is to acheive interleaving, then phone support would be correct. The memory doesn't have to be the same sizes, but if they aren't you will not have interleaving.

[RufusG]

Anyone suggest what improvement in performance can be achieved by memory interleaving ?

[RufusG]

I have just added a second DIMM to my ML110 G2 to create a dual memory channel system

The DIMMs have to be in matched pairs and installed in the correct sockets ie DIMM 2 & DIMM 4

With only a single DDR3200 DIMM the Memory Bandwidth was 2947 MHz

With the second DIMM - in the right slot - the memory Bandwidth went up to 4664 MHz

In the wrong slot, there was no change in Memory Bandwidth !

Tests done with SiSoft SANDRA benchmarking tool.

Other tests showed that the Front Side Bus went from 400MHz to 800MHz.

According to some documents from Intel, Infineon & Kingston this could enable a 10-25% overall performance improvement.

And only for adding a second matching DIMM !!!

Why doesn't HP supply the Servers with pairs of DIMMs ?

Why doesn't the documentation make this clearer ?

[Oleg Koroz]

here is more info

And only for adding a second matching DIMM !!!
http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00260539/c00260539.pdf
Page 26

Why doesn't HP supply the Servers with pairs of DIMMs ?
http://h18000.www1.hp.com/products/quickspecs/12161_na/12161_na.HTML
... optional interleaving....

Why doesn't the documentation make this clearer ?
http://h18004.www1.hp.com/products/servers/technology/whitepapers/adv-technology.html#2


http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c00383415&locale=en_US
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c00380186&locale=en_US

[RufusG]

Thanks for these HP documents

None of them explain that fitting DIMMs in matched pairs - in the correct slots - can give a 10-25% improvement in performance !

You must populate both Blue or Black sockets with matched pairs of DIMMs

Read up on the Dual Memory Channel:

http://www.intel.com/design/chipsets/dual_ddr_sb.pdf

http://www.kingston.com/newtech/MKF_520DDRWhitepaper.pdf

Regards

RufusG

[RufusG]

I have written a document about the performance improvement to be gained by installing DIMMs in matched pairs

- in the correct sockets

Please see the attached document:

Improving the Memory Performance of the ProLiant ML110 Server

[RufusG]

The attachment did not upload

If anyone wants a copy of the document, please email me at: rufus@greenbaum.com

Regards

RufusG