Hardware Reference Guide HP ProOne 400 G1 All-in-One

In addition, the computer supports:
1-Gbit, 2-Gbit, and 4-Gbit non-ECC memory technologies
single-sided and double-sided SODIMMS
SODIMMs constructed with x8 and x16 SDRAMs; SODIMMs constructed with x4 SDRAMs are
not supported
NOTE: The system will not operate properly if you install unsupported SODIMM memory.
HP offers upgrade memory for this computer and advises that the consumer purchase it to avoid
compatibility issues with unsupported third-party memory.
18 Chapter 2 Hardware repair and upgrade