support.dell.com System Memory Upgrade 1-5
RIMM Installation Guidelines
You must install RIMMs in pairs. This means that the RIMM in each socket on one
MEC must be the same memory capacity, density, and speed as the corresponding
RIMM in the same socket on the other MEC. Also, for either channel A or B of each
MEC, if one socket contains a RIMM, then the other socket must contain either
another RIMM or a continuity RIMM (CRIMM).
As an example, if you install only one pair of RIMMs in the RIMM1_A socket of each
MEC, then you must install a CRIMM in socket RIMM2_A of each MEC. Channel B
(sockets RIMM3_B and RIMM4_B) may remain empty, or it may contain one or two
CRIMMs per MEC (see Figure 1-1).
However, if channel A contains two RIMMs and you want to install additional R IMMs,
the preceding rules also apply for channel B.
NOTES: If 512-MB RIMMs are used, they must be populated starting with the bottom
RIMM socket (RIMM4_B, the one closest to the system board) and working up. For
example, see the configuration in the last row in Table 1-1. In this example, you would
insert the 512-MB RIMMs into the bottom three sockets (RIMM4_B, RIMM3_B,
RIMM2_A) and insert a CRIMM into the topmost socket (RIMM1_A).
When you add 512-MB RIMMs from a customer kit, you must remove all existing
RIMMs and reinstall the new 512-MB RIMMs, beginning with socket RIMM4_B and
working up on each riser board in mirror fashion.
Dell does not recommend or support the mixing of old and new 512-MB RIMMs in
sockets RIMM1_A and RIMM2_A.

Table 1-1. Sample Factory-Installed RIMM Configurations (per MEC)

For Total
Desired
Memory:
Populate both MECs as follows:
RIMM1_A (top) RIMM2_A RIMM3_B
RIMM4_B
(bottom)
128 MB CRIMM 64 MB Empty Empty
256 MB CRIMM 128 MB Empty Empty
384 MB 128 MB 64 MB CRIMM Empty
512 MB 128 MB 128 MB CRIMM Empty
512 MB CRIMM 256 MB Empty Empty
768 MB 256 MB 128 MB CRIMM Empty
1024 MB 128 MB 128 MB 128 MB 128 MB
1024 MB 256 MB 256 MB CRIMM Empty
1536 MB 256 MB 256 MB 256 MB CRIMM
2048 MB 256 MB 256 MB 256 MB 256 MB