*-memory description: System Memory physical id: 33 slot: System board or motherboard size: 4Gi B *-bank:0 description: DIMM [empty] physical id: 0 slot: Channel A-DIMM0 *-bank:1 description: DIMM [empty] physical id: 1 slot: Channel A-DIMM1 *-bank:2 description: SODIMM DDR3 Synchronous 1333 MHz (0.8 ns) product: AD73I1C1674EV vendor: Fujitsu physical id: 2 serial: 43D30100 slot: Channel B-DIMM0 size: 2Gi B width: 64 bits clock: 1333MHz (0.8ns) *-bank:3 description: DIMM [empty] physical id: 3 slot: Channel B-DIMM1 ubuntu@ubuntu ~ % sudo dmidecode -t memory | grep -c '^Memory Device$' 4 ubuntu@ubuntu ~ % sudo dmidecode -t memory | grep -c -Po '^\t Part Number: (?!
\[Empty\])' 1 ubuntu@ubuntu ~ % sudo dmidecode -t memory | grep -Po '^\t Maximum Capacity: \K.*' 32 GB This is a very informative command because it shows the number of empty RAM slots, the number of RAM slots that have RAM sticks installed and the size of each installed RAM stick.
The command to show the maximum RAM capacity (the maximum size that you can increase the RAM to) is: $ sudo dmidecode --type 17 | grep 'Memory Device' --count 4 $ sudo dmidecode --type 17 | grep -i size Size: No Module Installed Size: No Module Installed Size: 4096 MB Size: 4096 MB $ sudo inxi -m | grep capacity Array-1 capacity: 32 GB devices: 4 EC: None shows the number of slots available for the controller.
There are up to 4 DMI types, 2 can be memory arrays, and 2 can be specific slots. The information in dmidecode/inxi is extremely unreliable when it comes to the array data, but the actual slot data is generally very reliable.
If you are looking into buying or upgrading RAM, you should always check the product specifications to make sure that what inxi/dmidecode reports is actually correct.
This goes in particular for maximum RAM size and array capacities.
The above mentioned PCI bus types may be mixed on a single mainboard, because chipsets, especially these types for server appliance, support different PCI bus types at the same time.
The following pictures will allow you to identify the different PCI bus types as of the used socket type.
The top of each picture represents the backside of the mainboard, e.g.
The slot bracket will be placed there if PCI extension card is plugged into the slot.
Please note the coding nose near the backside which will identify a 3.3V only slot and prevent a 5V only card from being inserted because this might damage board or card.
On the market you will find various PCI extension cards using different bus width and signaling voltages.