The Importance of Server Memory

To ensure that you have the best understanding of our reliable, high-quality memory products, we offer the following glossary of important terms.

The Dataram Dictionary


The smallest unit of information a computer processes. A bit is 1 or 0.


A holding area for data shared by devices that operate at different speeds or have different priorities. A buffer allows a device to operate without the delays that other devices impose.

Buffered Memory

A memory module that contains buffers. Buffers re-drive the signals through the memory chips and allow the module to include more memory chips. Buffered and unbuffered memory cannot be mixed. The design of the computer memory controller dictates whether memory must be buffered or unbuffered.


Eight bits of information. The byte is the fundamental unit of computer processing; almost all specifications and measures of computer performance are in bytes or multiples thereof. See kilobytes and megabytes.

Cache Memory

A small amount (normally less than 1MB) of high-speed memory residing on or close to the CPU. Cache memory supplies the processor with the most frequently requested data and instructions. Level 1 cache (primary cache) is the cache closest to the processor. Level 2 cache (secondary cache) is the cache second closest to the processor and is usually on the motherboard.


Microchips that support the CPU. The chipset usually contains several controllers that govern how information travels between the processor and other components.

CPU (Central Processing Unit)

The computer chip that has primary responsibility for interpreting commands and running programs. The CPU is also known as the processor or microprocessor.

DIMM (Dual In-line Memory Module)

A printed circuit board with gold contacts and memory devices. A DIMM is similar to a SIMM, but with this primary difference: unlike the metal leads on either side of a SIMM, which are "tied together" electrically, the leads on either side of a DIMM are electrically independent.

DRAM (Dynamic Random-Access Memory)

The most common form of RAM. DRAM can hold data for only a short time. To retain data, DRAM must be refreshed periodically. If the cell is not refreshed, the data will disappear. (Also Dataram’s NASDAQ Id.)


A memory module having two banks.

Dual Channel

Based on the dual channel system board designs, memory modules are installed on two separate channels, each with it’s own access route to the memory controller. The dual memory channel design doubles the peak bandwidth of single memory channels. Best results occur when a matched-pair memory kit is used ensuring that the modules are identical.

Frontside Bus (FSB)

The data path that runs between the CPU and main memory (RAM).


Approximately 1 billion bits, or exactly 1 bit x 1,024³ (1,073,741,824) bits.


Approximately 1 billion bytes, or exactly 1 byte x 1,024³ (1,073,741,824) bytes.


Approximately one thousand bits, or exactly 1 bit x 2 to the 10th power (1,024) bits.


Approximately one thousand bytes, or exactly 1 byte x 2 to the 10th power (1,024) bytes.

Level 1 Cache (L1)

Also known as primary cache, L1 Cache is a small amount of high-speed memory that resides on or very close to the processor. L1 Cache supplies the processor with the most frequently requested data and instructions.

Level 2 Cache (L2)

Also known as secondary cache, L2 Cache is a small amount of high-speed memory close to the CPU and usually on the motherboard. L2 Cache supplies the processor with the most frequently requested data and instructions. Depending on the motherboard, Level 2 cache may be upgraded.


Approximately one million bits, or exactly 1 bit x 1,024² (1,048,576) bits.


The most common term used to denote the capacity of a memory module. One megabyte equals approximately one million bytes, or exactly 1 byte x 1,024² (1,048,576) bytes.


A computer's random-access memory. Memory temporarily holds data and instructions for the CPU. See RAM.

Memory Bus

The bus that runs from the CPU to the memory expansion slots.

RAM (Random-Access Memory)

A memory cell configuration that holds data for processing by a central processing unit (CPU). Random means the CPU can retrieve data from any address within RAM. See also Memory.


A data-holding device, such as a hard disk or CD-ROM.

Unbuffered Memory

Memory that does not contain buffers or registers located on the module. Instead, these devices are located on the motherboard.

Virtual Channel Memory (VCM)

VCM is a memory architecture developed by NEC. VCM allows different blocks of memory-each with its own buffer-to interface separately with the controller. This way, system tasks can be assigned their own virtual channels. Information related to one function does not share buffer space with other tasks running simultaneously, thereby making overall operations much more efficient.