topic Re: BL460 G6 memory controller speed in BladeSystem - General

BL460 G6 memory controller speed

Jim Brewster — Tue, 09 Jun 2009 18:17:28 GMT

I noticed in the BIOS setup that there's an option to set memory speed when using 2 DIMMs per channel to 1333 or 1066 mhz.

The quickspec seems to indicate that the memory speed is set automatically based on number and type of DIMMs. With 2 DIMMs per channel it should go to 1066.

What happens if I override this to 1333 in the BIOS setup?

Re: BL460 G6 memory controller speed

WFHC-WI — Tue, 09 Jun 2009 18:53:15 GMT

Hi Jim,

The processor rules will trump the BIOS setting. Regardless of the change you make here your memory bus will be 1066 (unless you have 2x 4GB quad-ranks installed).

My guess is that this option is provided only for slowing down the bus (maybe in a cluster with non-identical hardware?) I recommend not setting it to a speed higher than that specified in the quickspecs.

Good luck!

Re: BL460 G6 memory controller speed

Jim Brewster — Tue, 09 Jun 2009 19:03:05 GMT

Thanks for the response.

Is there anyway in BIOS or thru some utility to determine the actual memory controller speed that has been selected?

We've been running some memory benchmarks with 1 and 2 DIMMs per channnel and we don't see any performance differences.

Re: BL460 G6 memory controller speed

WFHC-WI — Wed, 10 Jun 2009 16:23:30 GMT

I'm not sure of any HP applications that would give you this information...

I recommend using a third-party utility such as Everest, available here:
http://www.lavalys.com/products.php?lang=en

hth

Re: BL460 G6 memory controller speed

Daniel Bowers — Thu, 11 Jun 2009 16:38:36 GMT

The BL460c G6 can actually run 2 DIMMs per channel at 1333. The Intel spec for the processor says that 2 DIMMs per channel is maximum 1066, but HP qualified it at 1333.

This is the one case where BIOS won't automatically set the speed to the maximum possible -- to do 2 DIMMs per channel at 1333, you have to set that BIOS setting. Otherwise, you'll get 1066.

Lots of info here:
http://h20195.www2.hp.com/v2/GetPDF.aspx/c01750914.pdf

Re: BL460 G6 memory controller speed

Daniel Bowers — Thu, 11 Jun 2009 16:41:08 GMT

Oops, forgot one caveat -- WFH-WI is right; some of the lower processor speeds can't do memory at 1333. (Some can't even do 1066).

Re: BL460 G6 memory controller speed

Jim Brewster — Thu, 11 Jun 2009 18:29:42 GMT

Awesome, thanks for info and link!

Re: BL460 G6 memory controller speed

Brian Proteau — Tue, 16 Mar 2010 15:27:20 GMT

I had a couple questions regarding the "Memory Speed with 2 DIMMs per channel" BIOS setting.

We have just purchased DL380 G6 servers with 96GB. I specifically populated it with 12-8GB 1333MHz DIMMS (2 per channel) to maintain that speed.

From the link to the G6 memory doc it appears I will need to change this setting to "1333 MHz Maximum" in order to realize these speeds.

Is that all correct?