Memory Module Configuration and Population Order

When you increase the memory configuration on a server module, consider the following configuration rules and population guidelines .

Configuration Rules

Server Module

Memory Module Configuration Rules

X8400, X8420, X8440

  • DIMMs must be installed in pairs.

  • Each pair of DIMMs must be identical with respect to manufacturer, size, and speed.

  • If the CPU has only a single DIMM pair, then you must install that single DIMM pair into the farthest slot locations from the respective CPU. For example:

    • The farthest slot locations on an X8400 Sun Blade Server Module are slot locations 0 and 1.

    • The farthest slot locations on an X8420 Sun Blade Server Module are slot locations are 2 and 3.

    • The farthest slot location on an X8440 Sun Blade Server Module are slot locations 6 and 7.

For more information about the order in which DIMMs should be populated on a server module, see the Population Order table below.

X8450

  • To achieve best performance, Fully Buffered (FB) DIMMs on the X8450 Server Module should be installed in groups of four. However, it is possible to populate FB-DIMMs on an X8450 server module in pairs. FB-DIMM pairs will not offer optimal performance unless the pairs are balanced symmetrically with a comparable pair of FB-DIMMs.

  • If you want to achieve maximum performance, then you should install FB-DIMMs in groups of four and follow these guidelines:

    • FB-DIMMs within a group of four must be identical with respect to size and speed. In addition, FB-DIMM pairs within a group of four should be identical with respect to manufacturer.

    • FB-DIMMs within a group of four must be installed in the appropriate color-coded slots. The color-coded group slots alternate between black and white. There are four single slots for each color-coded group.

    • Install FB-DIMMs in groups of four per the Population Order table below for the X8450 Server Module.

  • If you want to install the minimum increment of FB-DIMMs, then you should install a pair of FB-DIMMs and follow these guidelines:

    • FB-DIMM pairs should be identical with respect to manufacturer, size and speed.

    • The FB-DIMM pairs must be installed in the next available color-coded slot per the X8450 population rules described in the table below. The color-coded group slots alternate between black and white. There are four single slots for each color-coded group. You would need to install the first DIMM pair in the first two slots in a color-coded group, then the next time you increment the FB-DIMMs with a pair, you would install the second FB-DIMM pair in the adjacent two slots in that color-coded group.

  • The maximum supported memory capacity is 128 Gbytes (32 FB-DIMMs x 4G FB-DIMMs = 128-GB total). Support for larger capacity FB-DIMMs may be offered as they become available

Population Order

Server Module

Memory Module Population Order

X8400

  • DIMMs must be installed in pairs.

  • Each CPU supports up to four DIMMs

  • DIMM pair 0 (DIMM slots 0 and 1) is the pair farthest from the CPU.

  • DIMM pair 1 (DIMM slots 2 and 3) is the pair nearest to the CPU.

X8420

  • DIMMs must be installed in pairs.

  • Each CPU supports up to four DIMMs

  • DIMM pair 0 (DIMM slots 0 and 1) is the pair nearest to the CPU.

  • DIMM pair 1 (DIMM slots 2 and 3) is the pair farthest from the CPU.

X8440

  • DIMMs must be installed in pairs.

  • DIMM slots 0 and 1 is the pair nearest to the CPU.

  • DIMM slots 6 and 7 is the pair farthest from the CPU.

  • Each CPU supports up to 8 DIMMs.

  • 2-DIMM configuration has slots 6, 7 installed.

  • 4-DIMM configuration has slots 4, 5, 6, 7, installed.

  • 6-DIMM configuration has slots 2, 3, 4, 5, 6, 7, installed.

  • 8-DIMM configuration has slots 0, 1, 2, 3, 4, 5, 6, 7, installed.

Note

The X8440 processor supports single or dual channel DIMM configurations. For more information, see X8440 Dual or Single Channel DIMM Options.

Available X8440 DIMM Configurations:

  • 2-DIMM. DIMM pair 3 (DIMM slots 6 and 7 installed).

  • 4-DIMM. DIMM pairs 2 and 3 (DIMM slots 4, 5, 6, and 7 installed)

  • 6-DIMM. DIMM pairs 1, 2, and 3 (DIMM slots 2, 3, 4, 5, 6, and 7 installed).

  • 8-DIMM. DIMM pairs 0, 1, 2 and 3 (DIMM slots 0, 1, 2, 3, 4, 5, 6, and 7 installed).

X8450

FB-DIMMs Group of Four Population Order

Follow these population rules when you are installing FB-DIMMs in groups of four:

  • FB-DIMM within a group of four must be installed in the appropriate color-coded slots. The color-coded group slots alternate between black and white. There are four single slots for each color-coded group.

  • Populate the FB-DIMMs in groups of four in the following order:

    • The first group of four DIMMs must be installed in the center black color-coded slots.

    • The second group of four DIMMs must be installed in the white color-coded slots that appear on either side of the first group of DIMMs installed.

    • Subsequent DIMM groups (SDG) must be installed in the remaining six color-coded group slots.

FB-DIMM Single Pair Population Order

Follow these population rules when increasing the memory configuration with a single DIMM pair:

  • The FB-DIMM pair must be installed in the appropriate color-coded slots. The color-coded group slots alternate between black and white. There are four single slots for each color-coded group.

  • Install the first DIMM pair in two adjacent black color-coded slots located in the center.

  • The next time you increment the memory configuration with a single pair, you should install the second FB-DIMM pair in the two remaining black color-coded (adjacent) slots located in the center.

  • Subsequent groups of single DIMM pairs must be installed in the remaining seven color-coded group slots.

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