AB455A HP 8 GB (2×4 GB) DDR2-533 Memory Pair

AB455A is the HP 8 GB (2 x 4 GB) DDR2-533 memory pair, 4200 MB/s, single rank and registered. Each DIMM in the pair is a 4.0 GB double data rate 2 (DDR2) module with the number A9849-69001.

AB455A is the largest of the three pair products of the HP 9000 rp7440, above AB453A (2 GB) and AB454A (4 GB). Its DIMM size is 4096 MB, and with that one DIMM size the system tops out at 128 GB. The HP 9000 rp8440 also takes AB455A. Memory modules from the rp7410, rp7420 and rx7620 do not carry forward to the rp7440.

The pair is two DIMMs of equal size, and memory comes in three densities: 2 GB (2x1024 MB), 4 GB (2x2048 MB) and 8 GB (2x4096 MB). The smallest amount is 2 GB per cell. Larger DIMMs go in first across a cell, and the smaller ones follow. Pairs are placed in the order (0A, 0B) through (7A, 7B), which is eight pair positions on each cell board.

The system maximum of 128 GB is sixteen 4 GB DIMM pairs. For 64 GB per cell the recommended configuration is sixteen 4 GB DIMMs, and for 48 GB per cell it is eight 4 GB DIMMs in the first four pair positions with eight 2 GB DIMMs after them. Other mixes are supported while the loading rules are met. A cell board supports up to 16 DIMMs and 16 GB/s of peak memory bandwidth.