IBM RS/6000 SP, Handbook

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Chapter 2. SP internal processor nodes
39
For the best memory-access bandwidth, memory DIMMs should be distributed
evenly across four memory cards. As an example, you can realize better
bandwidth by using four bank of 128 MB DIMMs (4 GB total) distributed evenly
over four memory cards rather than by using one bank of 512 MB DIMMs (4 GB
total) on one memory card. The following list illustrates this:
򐂰
1 to 16 GB memory mounted on one card yields 16.8 - 24.3% of peak
bandwidth
򐂰
2 to 32 GB mounted on two cards yields 35.5 - 48.5% of peak
򐂰 4 to 64 GB mounted on four cards yields 67 - 97% of peak
Table 2-4 shows the memory features for the 375 MHz POWER3 SMP High
Node.
Table 2-4 375 MHz POWER3 SMP High Node (F/C 2058) memory features
Feature Code Description Minimum Node
Requirement
Maximum
Allowed Per
Node
4880 Base memory card 1 4
4133 1 GB - (8 x 128 MB DIMMs) 1 16
4402 2 GB – (16 x 128 MB DIMMs) 0 8
4403 3 GB – (24 x 128 MB DIMMs) 0 4
4104 4 GB – (32 x 128MB DIMMs) 0 4
4134 2 GB – (8 x 256 MB DIMMs) 0 16
4412 4 GB – (16 x 256 MB DIMMs) 0 8
4413 6 GB – (24 x 256 MB DIMMs) 0 4
4414 8 GB – (32 x 256 MB DIMMs) 0 4
4421 4 GB – (8 x 512 MB DIMMs) 0 16
4422 8 GB – (16 x 512 MB DIMMs) 0 8
4423 12 GB – (24 x 512 MB DIMMs) 0 4
4424 16 GB - (32 x 512 MB DIMMs) 0 4