HP Z820 Memory Slot Numbering — System Information Display and Documentation Differ

[DBrunnenmeyer]

The System Information display accessible while booting displays the size of the memory installed in each slot for each processor. For each of the two processors, the slot numbering is the same, DIMM1 - DIMM8. The information in the display does not differentiate between the two processors — CPU0 and CPU1.

The Maintenance and Service Guide says, for two processors, the slots are numbered DIMM1 through DIMM16, with the numbering beginning with DIMM1 for CPU 0 and DIMM2 for CPU 1 and so on, with DIMM15 for CPU 0 and DIMM16 for CPU 1. That same guide says that, for mixed DIMM sizes, that the largest pairs should be installed beginning with DIMM1 and the smallest pairs should be installed in the last higher-numbered pair of DIMM slots.

The machine I'm dealing with has eight 4GB DIMMs and eight 4GB DIMMs. Because of the difference in what is displayed in the (F9)  System Information screen accessible at start-up and what is stated in the instructions for installing the DIMMs in the manual, I cannot determine if the DIMMs are in the correct sockets.

The DIMM locations as displayed in  the System Information window are the same for each processor, as illustrated below:

DIMM1: 4   DIMM3: 4   DIMM 5: 2   DIMM7: 2

DIMM2: 2  DIMM4: 2    DIMM6: 4   DIMM8: 4

WHAT ARE THE CORRECT SLOTS FOR THESE DIMMs, ASSUMING THEY SHOULD BE INSTALLED IN PAIRS IN DIMM SLOT PAIRS IN ORDER OF DECREASING SIZE TO OBTAIN MAXIMUM PERFORMANCE?

Quick feedback would be appreciated, as I need to turn this machine over to a client sometime later this week.

[DBrunnenmeyer]

That should read eight 4GB DIMMs and eight 2GB DIMMs for a total of 48GB of RAM.

[Brian1965 · Accepted solution]

The 4GB DIMMs in the black slots, the 2GB DIMMs in the white slots. The BIOS is mapped as per the screen legend on the PCB which identifies the various board components. Page 106 in the Maintenance and Service Guide simply indicates the installation sequence for the DIMMs.

[DBrunnenmeyer]

Thank you for your help by clarifying the documentation.