Dell Precision 620 System Documentation Update (Memory Upgrade) - Page 9

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). However, if channel A contains two RIMMs and you want to install additional RIMMs, 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. 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. Sample Factory-Installed RIMM Configurations (per MEC) For Total Desired Memory: 128 MB 256 MB 384 MB 512 MB 512 MB 768 MB 1024 MB 1024 MB 1536 MB 2048 MB Populate both MECs as follows: RIMM1_A (top) CRIMM CRIMM 128 MB 128 MB CRIMM 256 MB 128 MB 256 MB 256 MB 256 MB RIMM2_A 64 MB 128 MB 64 MB 128 MB 256 MB 128 MB 128 MB 256 MB 256 MB 256 MB RIMM3_B Empty Empty CRIMM CRIMM Empty CRIMM 128 MB CRIMM 256 MB 256 MB RIMM4_B (bottom) Empty Empty Empty Empty Empty Empty 128 MB Empty CRIMM 256 MB support.dell.com System Memory Upgrade 5