单列直插式内存模块 (SIMM)是在固定 RAM 芯片的地方带有凹槽的小电路板。 SIMM 连接器以及位于主板上的插槽由金属(金或锡)制成。在 SIMM 中，存在于任一方面的引脚是连接的。 SIMM 有两种类型，一种是 30 引脚，另一种是 72 引脚。
双列直插式内存模块 (DIMM)还具有几乎与 SIMM 类似的金属连接器，但是连接器的任何一个周边都不允许相反。 DIMM 支持 64 位通道进行数据传输，而 SIMM 最多仅支持 32 位通道。现代主板使用的 DIMM 内存有三种，一种是 168 针，第二种是 184 针，第三种是 240 针。
SIMM 只有一个可用的方面，因为只有一组工具，而 DIMM 在任一侧都有完全不同的信号引脚，可以平方测量可用并且不相信相反的一侧。
让我们看看黑白 SIMM 和 DIMM 的区别：
| S.NO | SIMM | DIMM |
|---|---|---|
| 1. | In SIMM, Pins present in either facet are connected. | DIMM pins are freelance. |
| 2. | SIMM supports 32 bit channel for data transferring. | DIMM supports 64 bit channel for data transferring. |
| 3. | SIMM consumes 5 volts of power. | DIMM consumes 3.3 volts of power. |
| 4. | SIMM provides the storage 4 MB to 64 MB. | DIMM provides the storage 32 MB to 1 GB. |
| 5. | The classic or most common pin configuration of the SIMM module is 72 pins. | The foremost common pin configuration of the DIMM module is 168 pins. |
| 6. | SIMMs are the older technology. | DIMMs are the replacement of the SIMMs. |
| 7. | SIMMs are installed in pairs at a time. | DIMMs are installed one at a time. |
| 8. | SIMMs are used by 486 CPU as well as early Pentium computers. | DIMMs are used by modern Pentium computers. |
| 9. | The length and width of SIMM are respectively 4.25 inches and 1 inch. | The length and width of DIMM are respectively 1.67 to 5.25 inches and 1 to 1.75 inches. |
| 10. | There are single notches in SIMMs. | There are two notches in DIMMs. |