RAM

All ram speeds and transfer rates you need to know for A+

Dynamic RAM

Stores each data bit as an electrical charge within a single bit cell

Synchronous DRAM (SDRAM)

Speed is synchronized to the motherboard system clock

Double Data Rate SDRAM (DDR SDRAM)

Makes two data transfers per clock cycle

DDR3 Data Rate

800 to 2133 MT/s

DDR3 Transfer Rate

6.4 to 17.066 GB/s

DDR3 Maximum Size

8 GB

DDR4 Data Rate

1600 to 3200 MT/s

DDR4 Transfer Rate

12.8 to 25.6 GB/s

DDR4 Maximum Size

32 GB

DDR5 Data Rate

4800 to 6400 MT/s

DDR5 Transfer Rate

38.4 to 51.2 GB/s

DDR5 Maximum Size

128 GB

Small Outline DIMM (SODIMM)

Laptop RAM

Single-channel

There is one 64-bit data bus between the CPU, memory controller, and RAM devices

Dual-channel

There are two 64-bit pathways through the bus to the CPU

Quadruple-channel

In these architectures, if the full complement of modules is not installed, the system will revert to as many channels as are populated

Error correcting code (ECC) RAM

Used for workstations and servers that require a high level of reliability, 72-bit data bus rather than the regular 64 bits