Link to home
Start Free TrialLog in
Avatar of CnicNV
CnicNV

asked on

Mixing RAM densities in a Dell server?

We have a Dell PowerEdge gen 12 server that is capable of a total 384 GB of RAM and has 12 RAM slots total.  Currently, we have a total of 32 GB of RAM occupying 4 slots at 8 GB each.

I would like to upgrade this server at some point in the future using higher density RAM of the same specifications as RAM prices go down, making maximum use of the slots available.  But I would like to of course continue to be able to use the existing ones.

My question is, can I mix RAM density types if all other specs and brand are exactly the same?  My guess is yes, but just wanted to double check.  Also, I am guessing that they will need to be paired in some sort of slot staggered order?

Thanks.
Avatar of Neil Russell
Neil Russell
Flag of United Kingdom of Great Britain and Northern Ireland image

Unlikely if it is a newer server.  Please specify exactly what server you have as they will specify exactly what memory configurations are available for that model based on what processor configuration you have.
Avatar of Seth Simmons
sure, you can add 16gb modules if you wanted, but no more than 2 different sizes
for number of modules, depends if you have 1 or 2 processors
you can add a 16gb module if you have one processor but have to put 2 modules if you have 2 processors (1 in each channel)

if you have 2 processors, you can add 8 16gb modules giving you an additional 128gb
of course, how much of that you can use is dependent on the operating system
Avatar of Member_2_231077
Member_2_231077

Just about every new Intel or AMD based server lets you mix capacities and even speeds and number of ranks, the only hard and fast rule is you can't mix RDIMMs with UDIMMs or LRDIMMs. Population rules vary slightly and it's a fraction faster having the same amount of RAM on each memory channel, you've probably got 3 or 4 channels per CPU. Try to ensure the same of amount of RAM on each CPU.

384GB suggests 12 * 32GB dual rank DIMMs max, if you confirm the machine you have someone will recommend what to put in which slot.
Silly me, that would be 12 * 32GB quad rank at 2DPC, there aren't 32GB dual rank although 32GB load reduced DIMMs look like 2 ranks to the CPU.
Avatar of CnicNV

ASKER

Sorry for the delay, holidays/their lead up and all that.

This server is a 12th generation Dell Poweredge r420 with 4 8GB RDIMM chips at 1600mhz.  So I am gathering from most of the feedback that as longs as I buy RAM that is of a "Dell supported" brand in the 1600mhz RDIMM configuration, mixing any densities up to 32 GB should be fine?
ASKER CERTIFIED SOLUTION
Avatar of Member_2_231077
Member_2_231077

Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
Avatar of CnicNV

ASKER

Ok perfect.  Thanks for the help :)