Thank Likonen and piorunz! https://support.hp.com/us-en/product/hp-t5740e-thin-client/4282707/manuals
from hp's QuickSpecs: Note: Minimum of 1GB and a maximum of 4GB* (2 X 2GB) can be supported (*Up to 1 GB may not be available with 32-bit operating systems due to system resource requirements.)
bios reports 4032M memory, missing 64M might be used by graphics cardit seems to me that hp says that problem of missing memory is with 32-bit OS, not with hp
