PC2100

PC2100 is a designation used for DDR SDRAM memory modules. It denotes a peak data transfer rate of 2.1 gigabytes per second (2100 MB/s), corresponding to DDR-266 memory. This means the memory can transfer 266 million data words per second on a 64-bit data bus, yielding about 2.1 GB/s theoretical bandwidth.

Desktop PC2100 modules used an 184-pin DIMM form factor and typically operated at around 2.5 volts. They are part of the DDR SDRAM generation and were marketed as an intermediate step between PC133 SDRAM and higher-speed DDR modules.

Module capacities commonly ranged from 64 MB to 256 MB, with many systems shipping with 128 MB or 256 MB per module. PC2100 was used in early- to mid-2000s desktops and workstations, often in boards designed for Intel Pentium 4 and contemporaries, before being superseded by PC2700 and later DDR standards.

Nowadays PC2100 is considered obsolete. The "PC2100" label is a marketing shorthand used by memory manufacturers to indicate the performance class and approximate bandwidth; the underlying technology is DDR SDRAM as defined by JEDEC. Compatibility depends on motherboard support for DDR memory and the correct DIMM type; modern systems use newer generations of DDR memory.