System Board Sets
DIGITAL Server 9100 Series User's Guide
1-17
4 GB Memory Board DIMM Configuration Restrictions
The following restrictions apply to DIMM configuration on the 4 GB memory board.
•
The first bank in the first row should be populated first. If BIOS does not detect a memory module in
the first row, it assumes that no memory is present. The first row is on the outside edge of the memory
board, furthest from the system board.
•
DIMMs are populated in groups of four; therefore, DIMMs are added in 2, 4, 6, or 8 groups.
•
The slowest DIMM on the board must occupy slot J1.
•
DIMMs within a bank must be of the same size and speed.
•
Use only 32 MB, 128 MB, or 256 MB DIMMs on the 4 GB memory board.
•
Use only 72-bit, 168-pin 60ns or 70 ns fast page mode DIMMs.
•
An LST SIMM board must be present in the LST SIMM socket whenever a memory module is
present in the memory slot.
•
The LST SIMM module is available in 256K and 1024K sizes. If both system boards contain an LST
SIMM module, the LSTs must be the same size.
•
When a memory configuration is increased to above 256 MB, the size of the LST SIMM must be
upgraded from 256K to 1024K.
Other Memory Board Considerations
•
For systems with eight processors, two memory boards with an equal amount of memory must be
installed.
•
For systems with less than eight processors, fill the memory board on the primary system board before
installing memory modules on the secondary system board.
•
Address Bit Permuting is a performance enhancing mode. It is supported for configurations with
these restrictions: there must be a power of 2 number of rows; all rows must the same size; and all
populated rows must be adjacent and start at row 0. BIOS does not permit Address Bit Permuting
with illegal configurations.
The table below shows the memory configurations that allow Address Bit Permuting (ABP):
Memory Size
(MB)
DIMM J1-J4
(Banks 1 & 2)
DIMM J5-J8
(Banks 3 & 4)
DIMM J9-J12
(Banks 5 & 6)
DIMM J13-16
(Banks 7 & 8)
ABP
Allowed?
512
32
32
32
32
Yes
2048
128
128
128
128
Yes
4096
256
256
256
256
Yes