What kind of memory is this?
Most of the memory we are run into at Free Geek, falls into one of two categories (DIMM and SIMM):
Dual Inline Memory Modules are newer and longer than the older SIMMs (see below). All DIMMs are the 5.25 inches long, and they can be distinguished by the number and positions of their notches.
Dual Inline Memory Modules son más recientes y más largo que los de más antiguos Simms (véase más adelante). Todos los módulos DIMM miden 5,25 pulgadas de largo, y pueden ser distinguidos por el número y las posiciones de sus muescas.
A stick of DDR has a single notch in it near the center of the stick, with gold pins missing from one side more than the other, as well as 2 rounded notches on each side
Un módulo de DDR tiene una muesca en en el centro del módulo.
The newer DDR2 has a single notch that is slightly nearer the center of the stick, so it will not fit into a regular DDR slot. That notch also has symmetrical missing gold pins on either side. Like DDR, there are 2 rounded notches on the sides of the stick as well.
The DDR3 stick also has a single notch on it that is slightly closer to the end than the DDR2, with symmetrical missing gold pins. On the sides, there are square notches as opposed to the rounded ones of DDR and DDR2.
A stick of RAMBUS has two notches in it at the center of the stick.
Un módulo de RAMBUS tiene dos muescas en en el centro del palo.
A stick of SDRAM has two notches in it, one near the center of the stick, and one closer to the side.
Un módulo de SDRAM tiene dos muescas, una cerca del centro del módulo, y otra cerca a un extremo del módulo.
Single Inline Memory Modules are older and shorter than the DIMMs. There are two varities, 30-PIN SIMMs and 72-PIN SIMMs. Both are substantially shorter than the DIMMs (above). We normally do not want to keep SIMMs these days.
72 Pin SIMM
72 pin SIMMS are 4.25 inches long. This is about the same length as a cache module, but the holes and notches to install them are different, see points A (side holes), B (center notch) and C (side notch) in the picture.
NOTE: The 72-PIN SIMM is not a DDR (because it's not a DIMM and all DDRs are DIMMs). Many people confuse these types of memory, because both have only one notch. The 72-PIN SIMM is much too short to be a DDR.
30 Pin SIMM
30 pin SIMMs are 3.5 inches long. These are the oldest types of memory we tend to see very often. Note that they do not have a center notch.