General Information  101
Memory(RIMM)
Your computer has four connectors for Rambus in-
line memory modules (RIMMs) that provide up to a 
maximum of 1.5 GB of system memory.
The IBM-installed RIMMs that come with your 
computer are ECC (error checking and correction) 
Rambus dynamic random access memory (RDRAM) 
modules.
When installing or replacing RIMMs, take the 
following information into consideration:
•
Rambus memory is divided into two 
channels (channel A and B). RIMM connectors 
1 and 3 are channel A, and RIMM connectors 2 
and 4 are channel B.
•
Each channel must contain the same 
amount of memory.
•
Each RIMM connector supports a 
maximum of 512 MB of memory.
•
Any connector that does not have a RIMM 
installed must have a continuity RIMM (C-
RIMM), a module that looks like a RIMM but has 
no memory on it.  A C-RIMM is used to continue 
the connection on a RIMM connector that does 
not have memory installed in it.
•
Install only ECC RIMMs to enable ECC.  If 
you use ECC and non-ECC memory together, it 
will function as non-ECC memory.
•
RIMM connectors do not support dual in-
line memory modules (DIMMs).
•
Use only PC600 or PC800 RIMMs.
NOTE: 
If you use PC600 and PC800 RIMMs together, 
all memory will function at the speed of the 
slowest RIMM.
Removing a RIMM or C-RIMM
To remove a RIMM or C-RIMM:
1.
To locate the RIMM connectors inside your computer.