HP Xw6200 - Workstation - 2 GB RAM Technical Reference Manual page 84

The BIOS generates warnings/errors on invalid memory configurations.
In DDR2 mode, dual-rank DIMMs are placed farther from the Memory Controller Hub (MCH) than
single-rank DIMMs.
If there is no way to obtain a valid memory configuration by disabling some of the plugged-in memory,
the BIOS will halt with a diagnostics 2004 code for memory error (4 beeps/blinks).
If the BIOS can find a valid memory configuration by disabling some of the plugged-in memory, it will
do so and will report a warning during POST ("215-mismatched memory"). The system can still be
booted in this condition.
To install a DIMM:
1 Disconnect power from the system (page 68), remove the access panel (page 74), lay the
workstation on its side with the system board facing up. If an airflow duct is installed, remove the
system fan assembly (page 80) to gain access to the DIMMs.
2 Gently push outwards on the socket levers.
3 Lower the DIMM straight down and be sure the socket levers secure the module into place.
84 REMOVAL AND REPLACEMENT PROCEDURES