Acnodes OPC 8190 - Manual (Page 28)

2.6 DRAM Installation
OPC8190 provides one 200-pin DDR2 SODIMM socket that
support system memory up to 2GB. Please follow steps below to
install the memory modules:
Step 1 Refer to section 2.1 to open the back cover and find
out DIMM socket on mainboard (SBC87830).
Step 2 Insert the DRAM to the DIMM socket, and then push it down
firmly until it is clipped by the socket.