MEM_A_SEL

MEM_B_SEL

MEM_A_RD

MEM_B_RD

MEM_A_WR

MEM_B_WR

UPA_DATA0<143..000> UPA_DATA1<143..000> UPA_DATA2<63..00> UPA_DATA3<71..00>

Marvin

ASIC

Memory interface

K9+

ASIC

MEM_ADDR

MEM_RASA2_L

MEM_RASA0_L

MEM_CASR2_L

MEM_CASR0_L

MEM_WRR2_L

MEM_WRR0_L

MEM_DAT<575..000>

Memory module

FIGURE C-3Memory System Functional Block Diagram

As shown in FIGURE C-4, the memory module is arranged in four banks. DIMMs are always accessed four at a time. Consequently, the DIMMs must be installed in groups of four (quad) and individual DIMMs within a bank must be of equal capacity. FIGURE C-5illustrates DIMM row mapping.

Caution Failure to populate a DIMM bank with DIMMs of equal capacity will result in inefficient use of memory resource or system failure.

Note For best system performance, install four identical DIMMs.

C-10Sun Ultra 60 Service Manual • August 2001

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