Compaq AlphaServer ES45 Service Manual page 219

Only the following DIMMs and DIMM options can be used in the ES45 system.
Density
128 MB
256 MB
512 MB
1 GB
∗ Toshiba specific DIMM and option.
CAUTION: Using different DIMMs may result in loss of data.
DIMM DIMM Option (4 DIMMs per)
20-01CBA-09 MS620-AA (512 MB)
20-01DBA-09 MS620-BA (1 GB)
20-01EBA-09 MS620-CA (2 GB)
20-L0FBA-09
MS620-DA (4 GB)∗
System Configuration and Setup 6-25