Memory Architecture; Dimms; Memory Block Diagram; Memory Array Capacities - HP Rx2620-2 - Integrity - 0 MB RAM Service Manual

Figure 1-5 Memory Block Diagram

Memory Architecture

The I/O ASIC memory interface supports two DDR cells. Each cell is 144 data bits wide. The
memory subsystem physical design uses a comb-filter termination scheme for the data and the
address and control buses. This topology is similar to other DDR designs. Clocks are distributed
directly from the I/O ASIC. Each clock pair drives two DIMMs.
Memory data is protected by the ECC. Eight ECC bits per DIMM protect 64 bits of data. The use
of ECC allows correction of single-bit errors, and detection of multi-bit errors. Only DIMMs with
ECC are qualified or supported.

DIMMs

The memory subsystem supports only DDR SDRAM (Double Data Rate Synchronous Dynamic
Random Access Memory) technology utilizing industry-standard PC-1600 type DDR SDRAM
DIMMs, 1.2" tall. The DIMMs use a 184-pin JEDEC standard connector.
DIMMs are loaded in a group of four, known as a quad. All four DIMMs in a quad must be the
same size. Table 1-2
Table 1-2 Memory Array Capacities
Mininum/Maximum Memory Size
1 GB / 3 GB
2 GB / 6 GB
4 GB / 12 GB
24 Introduction
summarizes the memory solutions.
Single DIMM Size
256 MB DIMM
512 MB DIMM
1024 MB DIMM
DDR SDRAM Count, Type, and Technology
18 x 32 MB x 4 DDR1 SDRAMs (128 MB)
36 x 32 MB x 4 DDR1 SDRAMs (128 MB)
36 x 64 MB x 4 DDR1 SDRAMs (256 MB)