Removal and replacement procedures 64
performance, and installing equal amounts of memory for both processors provides for best
performance.
• Install all memory modules of the same speed on the same processor for best performance.
• Install all memory modules of the same voltage on the same processor for best power.
Memory bus speed
Depending on the quantity and native speed of memory modules installed, memory bus speeds can be 1333
MHz, 1066 MHz, 800 MHz, or 667 MHz. Memory bus speeds can be different for each processor.
To determine memory bus speeds, do the following:
1. Within RBSU, select the Power Management Options menu > Advanced Power Management Options
menu > Maximum Memory Bus Frequency menu.
2. Select one of the following menu options:
o Auto (default)—The memory bus speed is set to what is shown in the following table. If the native
speed of the installed memory module is slower than the memory bus speed, the memory bus speed
is set to the memory module native speed
Memory
modules per
channel
QR SR or DR
Memory
module native
speed
Memory bus speed
(standard-voltage
memory module)
Memory bus speed
(low-voltage memory
module)
1
— 1* SR 1333 MHz
DR 1333 MHz
DR 1066 MHz
1333 MHz 1333 MHz
1
1 — QR 1066 MHz 1066 MHz 1066 MHz
2
— 2* SR 1333 MHz
DR 1333 MHz
DR 1066 MHz
1333 MHz 1333 MHz
2
1 1 SR 1333 MHz
DR 1333 MHz
DR 1066 MHz
QR 1066 MHz
800 MHz 800 MHz
3
— 3 SR SR 1333 MHz 1333 MHz 1066 MHz
3
— 3 DR DR 1333 MHz
DR 1066 MHz
1066 MHz 800 MHz
3
— 3 mixed SR 1333 MHz
DR 1333 MHz
DR 1066 MHz
1066 MHz 800 MHz
3
1 2 SR 1333 MHz
DR 1333 MHz
DR 1066 MHz
QR 1066 MHz
800 MHz 667 MHz
— *These are the only configurations supported by UDIMMs. All configurations listed in this table
are supported by RDIMMs.
— LVDIMM support is dependent on the ROM version.
— This table is for reference only. It may not be updated to reflect recent changes.
o 800 MHz—The memory bus speed is set to 800 MHz regardless of the quantity of memory modules
installed, unless the table above reflects a slower memory bus speed.
