Sharing different memory DIMMS

[Michael Tully]

I have an A550/2 that has 2x512 Mb DIMMS installed. I have some spare 256Mb DIMMS kicking around that I would like to install. I would like to know if these two different sized DIMMS will share happily.

[Patrick Wallek · Accepted solution]

Yes, they should work fine as long as those DIMMs are compatible with that particular machine.

The rules for different sized DIMMs is that the larger capacity go in the lower numbered slots.

So:

slot 0a....512 MB
slot 0b....512 MB
slot 1a....256 MB
slot 1b....256 MB
etc.

If you happen to have any 128 MBs those would work to, just install the next slots available after the 256's.

[Michael Tully]

Hi Patrick,

The reason I ask is that 1) This server is production, so I can't just take it out and hope. 2) I tried sharing some 256Mb DIMMs with some 128Mb ones on an A400 and it didn't work. (Yes I had the DIMMs in the right numbered slots) ;^)

Thanks for that I'll go and now pencil in an outage, if I can get one.

Cheers
Michael

[Bernhard Mueller]

Michael,

the only issues I had with different (large) sizes of DIMMs could always be resolved by upgrading the PDC firmware. Guess you double-checked that already. Update for A-class is easy and quick and you need a downtime anyway, so why not do it upfront?

Regards,
Bernhard

[Victor Fridyev]

Hi,

DIMMS with different sizes work perfectly, the problem (according fairy tales of my HP sales manager) may be in the fact that all DIMMS should be from the same HW vendor (HP, Kingston, etc)

Good Luck