Linux has a very handy function, dmidecode, that can be used to display useful information about the hardware configuration of a system. The more general purpose command hardinfo displays some of the same information but not all.
Basic usage is:
The output can be made more specific using one of the options described here. In my case, I wanted to know what the part number of the DRAM fitted to a system was while the system was running and without literally looking at the part. This command selects the memory information:
sudo dmidecode -t memory