Hardware Reference
In-Depth Information
FPM provides faster access to data that is stored in the same row of a memory
matrix.
Non-volatile random access memory (NVRAM)
See CMOS memory on page 44.
Registered memory
Registered memory is SDRAM memory that contains registers directly on the
module. The registers re-drive the signals through the memory chips and allow
the module to be built with more memory chips. Registered (buffered) and
un-buffered memory cannot be mixed. The design of the computer memory
controller dictates which type of memory the computer requires.
Synchronous dynamic random access memory (SDRAM)
Synchronous DRAM (SDRAM) is a DRAM technology that uses a memory
clock to synchronize signal input and output on a memory chip. The memory
clock is synchronized with the CPU clock so the timing of the memory chips
and the timing of the CPU are locked together. Synchronous DRAM saves time
in executing commands and transmitting data, thereby increasing the overall
performance of the computer. SDRAM allows the CPU to access memory
approximately 25% faster than EDO memory.
Self-refreshing RAM
Self-refreshing is a memory technology that enables DRAM to refresh itself
independently of the CPU or external refresh circuitry. Self-refresh technology
is built into the DRAM chip itself and reduces power consumption dramatically.
Notebook and laptop computers use this technology.
Synchronous graphics random access memory (SGRAM)
Synchronous graphics RAM is video memory that includes graphics-specific
read/write features. SGRAM allows data to be retrieved and modified in blocks
instead of individually. Blocking reduces the number of reads and writes the
memory must perform and increases the performance of the graphics controller.
Single inline memory module (SIMM)
Single inline memory modules are small printed circuit boards populated by
semiconductor memory devices and fitted with gold or lead/tin contacts. A
SIMM plugs into a memory expansion connector on the system board. SIMMs
offer various advantages over DIP packaged RAM including ease of installation
and minimal footprint. See also DIMM.
