Maximum Memory, Standard Memory and Slots
 

Maximum Memory

The is the maximum amount of memory supported by the system when it was originally released. Due to advances in DRAM (i.e. memory) technology this may be increased over time by the computer's manufacturer.

Standard Memory

This is the amount of memory included with the system (as stated by the manufacturer). It does not take into account upgrades installed at the time of purchase or later. "Removable memory" indicates that one or more of the memory slots are occupied with the standard memory, while "non-removable" indicates the standard memory does not occupy any of the memory slots, but is permanently affixed to the motherboard.

Slots

This is the total number of memory upgrade slots (sockets) followed by their configuration. Banks are the way a system addresses memory. A bank must be completely filled with memory modules of the same size and type in order for the system to recognize and address the memory. i.e. :
 3 (3 banks of 1) This indicates that there are 3 memory slots. These are divided into 3 banks, and each bank consists of one memory slot. So you can add memory one piece at a time for the system to use.
4 (2 banks of 2) This indicates that there are 4 memory slots. These are divided into 2 banks, and each bank consists of two memory slots. So you must add memory two pieces at a time (they must be the same size and type of memory) in order for the system to benefit from the upgrade.
12 (3 banks of 4) This indicates that there are 12 memory slots. These are divided into 3 banks, and each bank consists of four memory slots. So you must add memory four pieces at a time (and they must be the same size and type of memory) in order for the system to benefit from the upgrade.