Compaq AlphaServer ES40, Owner'S Manual

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5-22 ES40 Owner’s Guide
DIMM Information for Model 2 Systems
DIMMs are manufactured with two types of SRAMs, stacked and unstacked
(see Figure 5–10). Stacked DIMMs provide twice the capacity of unstacked
DIMMs, and, at the time of shipment, are the highest capacity DIMMs offered
by Compaq. The system may have either stacked or unstacked DIMMs.
You can mix stacked and unstacked DIMMs within the system, but not within
an array. The DIMMs within an array must be of the same capacity and type
(stacked or unstacked) because of different memory addressing.
When installing sets 0, 1, 2, and 3, an incorrect mix will not occur. When
installing sets 4, 5, 6, or 7, however, you must ensure that the four DIMMs
being installed match the capacity and type of DIMMs in the existing array. If
necessary, rearrange DIMMs for proper configuration.
Figure 5–10 Stacked and Unstacked DIMMs
PK1209
Unstacked DIMMs
Stacked DIMMs