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RAM Upgrade for DL385 G1

Tony Tuccillo
Occasional Visitor

RAM Upgrade for DL385 G1

I have a question about a client server. Our client's single CPU server curently has 4 512MB RAM modules installed and we recently tried to add additional RAM in the second set of RAM slots (bank c or d) using 2 appropriate 1GB modules and the server wouldn't recognise them in either bank. It powered up ok but it was like they were not even there. We tried replacing the RAM in Bank A with the new RAM and they worked ok there. My question is, would anyone know if there's any reason these RAM slots would be inactive and how to enable them?

juan quesada
Respected Contributor

Re: RAM Upgrade for DL385 G1

Memory Installation Guidelines

You must observe the following guidelines when installing additional memory:

1. Always install memory in pairs of two identical DIMMs. (This includes DIMM size and speed)
2. Install only ECC PC-3200 Registered SDRAM DIMMs that meet the following specifications:
* Supply voltage - 2.6 volts
* Bus width - 72 bits
3. Install DIMMs with the same speed.
4. Install DIMMs into both slots within a single bank.
5. Memory must be installed in pairs (banks) beginning with banks furthest away from each populated processor (banks B and D)
6. Install DIMM pairs with the smallest capacity in banks farthest from the processor.
7. Processor 2 may be installed without memory, but this may result in less than optimal performance.
8. Any memory installed into banks for processor 2 (5C - 8D) can be used only if processor 2 is installed.

Honored Contributor

Re: RAM Upgrade for DL385 G1

The reason for point 8 of the Memory Installation Guidelines: AMD's 64-bit CPUs (Opterons) integrate the memory controller into the CPU. The more usual solution is to put the memory controller in the northbridge chip on the system board.

Apparently the DL385 G1 is designed so that the memory controller of each CPU manages one set of RAM slots. When only one CPU is installed, the second set of slot lacks a memory controller... making the slots inactive.

To sum up: when a server has an Opteron CPU, the possible memory configurations may depend on the number of CPUs installed. It's best to check the documentation unless one is already familiar with a particular server model.