The difference between 1 DIMM and 2 DIMM is that the latter offers a faster speed for users because it has a larger memory component. DIMM is an acronym for Dual In-line Memory Module and it is a circuit board with memory chips.
A DIMM has 184 pins and has various pin configurations for the different DDR RAM modules. DIMM memory has a 64-bit path due to its Pentium Processor. DIMMs can also be installed on a computer hard drive one at a time because of their bit path which is different than SIMMs.
Another type of DIMM is the SO-DIMM, which is also known as Small Outline DIMM. It comes in a 72-pin and a 144-pin configuration. SO-DIMM memory is most commonly used in laptops.
DIMMs have several advantages over the other popular form of memory known as the Single In-Line Memory Module, or SIMM. DIMMs are able to have separate contacts on either side of the board so that there is twice as much data on a DIMM circuit board as there is on a SIMM circuit board. DIMMs are also able to speed up the loading effort of the memory because they are able to buffer the command address and control signals. SIMM memory comes in 72-pin or 30-in configurations and it is typically found in older computers.