Removal and Replacement Procedures Expansion Cards and Memory

DIMMs should be installed in pairs.

Do not mix DIMMs of different memory speeds. Performance will reflect the speed of the slowest DIMM.

Each DIMM within a pair should be identical in size. For example, a 256MB DIMM must be paired with a similar 256MB DIMM.

Each DIMM within a pair should be identical in technology. For example, you cannot mix a 256 MB 9-device DIMM with a 128MB 18-device DIMM on the same channel.

To identify which DIMM technology you are using, compare the memory size and number of DRAM components on the module. A 128 MB DIMM has 18 DRAM components that fully populate both sides of the module. A 256MB DIMM has 9 DRAM components; four on one side, five on the other.

The first pair of DIMMS should be installed in slots 1 and 2. The DIMM slots are numbered sequentially. Slot 1 is closest to the CPUs.

The second pair of DIMMS, if any, should be installed in slots 3 and 4.

DIMMs must be installed correctly. Be sure to match the keyed slot on the DIMM with the tab on the DIMM socket.

For optimal system performance, DIMMs should be installed in identical pairs in the following three configurations: slot 1 and 2, slot 3 and 4, or all DIMM slots populated in paired format.

If you are using a single DIMM configuration, the DIMM should be installed in slot 1 or slot 3.

Although a single-DIMM configuration is possible, it does not provide the optimal system performance that a dual-DIMM (dual-channel) of matching sizes, configuration provides.

If you are installing two DIMMs of different sizes, they can only be installed in slot 1 and slot 3 with each DIMM occupying either slot.

Although a mixed size dual-DIMM configuration is possible, it does not provide the optimal system performance that a dual-DIMM (dual-channel) of matching sizes, configuration provides.

No other memory configurations are supported. Attempts to install memory in other configurations will result in unpredictable system performance.

The following table provides acceptable pairing configurations but do not cover all module capacities. However, the same pairing configuration applies regardless of the module type and capacity.

 

Service Reference Guide

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