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Smart array 6404/256 memory reported as 192MB


Smart array 6404/256 memory reported as 192MB


I haver just installed a new 6404 with 256 MB ram on a Proliant DL380 G3.

At the startup (initialization) the 6404 is announced as having 192MB... The firmware is 1.60.

The Acu (6.40.11) also reports 192MB.

The HP Insight Diagnotics (4.0.663A) reports 256MB.

Does that mean anythting? Ist here any problem or is it only cosmetic?

Thanks for help

Kind regards

Leon Rosier
Respected Contributor

Re: Smart array 6404/256 memory reported as 192MB

Hi Philippe,

I think you should have it checked by HP. In my opinion this is not normal behaviour.

Barry Head
Occasional Visitor

Re: Smart array 6404/256 memory reported as 192MB

I have experienced exactly the same problem on two brand new ML370 G3 machines with brand new 6404/256 controllers. My supplier has even provided replacements for the controllers but these report the same memory.

I have located the following articles which may provide some further information:


Suggests that the controller already has 64MB on-board


Suggests that 'For the Sixth Generation (and later) Smart Array Controllers, Read and Write Cache Sizes are no longer differentiated. Instead, the ACU presents "Total Memory on Controller" (including both embedded memory and any installed cache)'

Does this mean that my '256MB' controllers (which contain memory chips labelled with a 256MB label) are actually mis-labelled 128MB controllers reporting the 128MB + 64MB built-in memory ?

Several telephone calls from my supplier to HP have failed to resolve the issue. Can anybody else throw any light on this please.

Barry Head
Occasional Visitor

Re: Smart array 6404/256 memory reported as 192MB

I've found the answer ! There appears to be one very important piece of information lacking from the documentation about the Smart Array 6404 controller - it is actually two controllers on one board ! I discovered this somewhere in the general specifications for the controller and suddenly everything fell into place as follows:

The Basic controller card has 64MB of onboard memory.

The SA6402 controller comes as standard with a 128MB Cache RAM module. As noted in the document referred to in my previous posting, on startup the controller will report the total RAM available to it, ie 64 + 128 = 192MB.

There are two optional extras for the SA6402 controller - a 256MB Cache RAM module and a card with an additional 2 channels.

The SA6404 controller is in fact a SA6402 with both these options factory fitted.

What is not widely mentioned is the fact that the card with the additional two channels actually contains an additional processor to increase the throughput. When you first start up a machine with a 6404 controller, it will report two controllers - a 6404 and a 6404-EM. The second controller is the additional card or expansion module. It appears that when this expansion module is in place, the 256MB RAM is shared between the two controllers, so they each report 128MB plus the 64MB base RAM on the card, or 192MB in total.

For our application we are only using internal drives so I do not need the additional channels. I mistakenly believed that buying the 6404/256 controller would give me the most powerful board. Having now discovered the above, I would have been better to buy the 6402/128 board and then the replacement 256MB memory module.

To prove this, I have removed the additional channel module from the card and restarted the machine. Startup reports only one controller and that the memory configuration has been automatically updated - it now shows 320MB of cache RAM.