Compression Attached Memory Module (CAMM) is a memory module form factor which uses a land grid array, and developed at Dell by engineer Tom Schnell as a replacement for DIMMs and SO-DIMMs which use edge connectors and had been in use for about 25 years.[1] The first SODIMMs were introduced by JEDEC in 1997.[2][3][4][5]
CAMM was created to overcome technical limitations of traditional slotted DIMM.[6] The CAMM module allows for shorter traces on the motherboard PCB as compared to SO-DIMM, allowing the memory to be run with less power and at higher speeds. The memory module is pressed and held in place against a bar with land grid array pin contacts which connect to the motherboard.
Advantages of CAMM include lower thickness, allows for replaceable LPDDR modules, faster speeds above 6400 MT/s, higher capacities up to 128 GB per module and higher memory bandwidth. Disadvantages are that it cannot be mounted without tools and uses six screws. Systems with installed CAMM memory already installed cannot be expanded through adding additional CAMM modules in the same way that 2 DIMMs can be added alongside 2 existing DIMMs to expand total system memory. Instead, the entire CAMM module must be replaced with one with a higher capacity. So CAMM may be of benefit for laptops and ITX systems.
The total number of interface contact points of CAMM is 616 (44 per row times 14 rows).[7]
SO-DIMMs, which were first introduced almost 25 years ago, haven't changed much in all that time besides moving to newer and faster DRAM methods.