mike27octMar '15 posted in another place:
Does this info help? It is from WD’s Data Sheet for the Business Series
Memory:
DL2100
1 GB, upgradable to 5 GB
with 4GB DDR3L DIMM
DL4100
2 GB, upgradable to 6 GB
with 4GB DDR3L SO-DIM
I don;t know if anyone has reported that adding a 8GB to get a total of 10 GB works.
here is more information about getting the correct memory type if you want to add 4 GB card.
