HP Kayak XA-s02 Supplementary Manual page 14

NOTE
Table 1 Compatibility of DIMMs
1.
Step 13: Adding/Replacing DIMMs
Upgrading Main Memory Modules
The PC Workstation has 64 MB of non-ECC SDRAM main memory
installed in one DIMM slot. Can a 256 MB ECC SDRAM memory
module be added to a second DIMM slot in order to upgrade the
memory?
No. To upgrade the memory, it is possible to add 64 MB or
128 MB memory modules (either ECC or non-ECC) to the
other 2 DIMM slots (up to a maximum of 320 MB). Alterna-
tively, you may remove the existing 64 MB memory module
and install up to 3 256 MB memory modules, for a total of
768 MB.
Main memory upgrades are available in 32 MB, 64 MB, 128 MB and 256 MB
ECC SDRAM modules. It is important to note that the 32 MB, 64 MB and
128 MB modules are non-buffered ECC SDRAM modules, while the 256 MB
modules are registered ECC SDRAM modules.
Non-buffered and registered ECC modules are not compatible with each
other, and cannot be mixed. See the table below for DIMM compatibility
rules.
Original
DIMM Type
Non-ECC
Non-buffered ECC
Registered ECC
(256 MB)
All DIMMs will function as Non-ECC.
14
Adding Adding
Non-ECC Non-buffered ECC
Yes Yes
1
Yes Yes
No No
Adding Registered
ECC (256 MB)
1
No
No
Yes