dmidecode tool dumps your system’s DMI (Desktop Management Interface) table contents in a human-readable format. This table contains information regarding system’s hardware components, as well as BIOS revisions etc. dmidecode output not only describes system current configuration, but also reports the BIOS limitations on supported CPU speed, Maximum Memory allowed and more.
Now lets say I want to restrict information to certain areas of DMI, I can do that by using the option -t and specifying what type of information I am interested in. For example, Processor Information is DMI type 4 and Memory Device is DMI type 17.