A type of SDRAM memory that uses registers to hold data for one clock cycle before it is moving it on and in so doing increases the reliability of high-speed data access. Registered memory modules are typically used only in server environments and other mission-critical systems. Registered and unbuffered memory cannot be mixed. the design of the processor's memory controller dictating which type is required.
The term registered refers to how the memory module processes signals. Registered modules contain a register that delays all information transferred to the module by 1 clock cycle. This type of memory is primarily used in servers and was designed for modules with 32 or more chips on them to help ensure that data is properly handled.
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 and unbuffered memory cannot be mixed. The design of the computer memory controller dictates which type of memory the computer requires.