Type of Computer RAM's

RAM means Random Access Memory, your computer processor uses RAM to store some of the data needed to make your programs work.

RAM is used millions of times every second. A computer uses Ram to hold temporary instructions and data needed to complete tasks.

This enables the computer's Central Processing Unit (CPU), to access instructions and data stored in memory in speedy manner.

Computer memory is crucially important to computer operation. Files and programs are loaded into memory from external media like hard drives and removable disks

Memory can be built right into a system board, but it is more typically attached to the system board in the form of a chip or module. Inside these chips are microscopic digital switches, which are used to represent binary data.


There are three main types of RAM:

SDRAM
DDR
Rambus DRAM.


SDRAM (Synchronous DRAM)
168-pin SDRAM DIMMs. SDRAM started out running at 66 MHz able to scale to 133 MHz (PC133) up to 180MHz or higher.

DDR (Double Data Rate SDRAM)
DDR basically doubles the rate of data transfer of standard SDRAM. DDR memory operating at 333MHz actually operates at 166MHz times 2 (PC333 / PC2700) or 133MHz times 2 (PC266 / PC2100) it has 2.5 volt technology that uses 184 pins in its DIMMs. Incompatible with SDRAM physically, but uses a similar parallel bus

Rambus DRAM (RDRAM)
RDRAM is a serial memory technology in three kinds, PC600, PC700, and PC800. PC800 RDRAM double the maximum throughput of old PC100 SDRAM, but a higher latency. RDRAM designs with multiple channels, such as those in Pentium 4 motherboards.

DIMMs vs. RIMMs

DRAM comes in two major forms: DIMMs and RIMMS.

DIMMs are 64-bit components, but if used in a motherboard with a dual-channel configuration like Nvidia nForce chipset you must pair them to get maximum performance.

DIMMs for SDRAM and DDR are different, and not physically compatible. SDRAM DIMMs have 168-pins and run at 3.3 volts, while DDR DIMMs have 184-pins and run at 2.5 volts.

RIMMs use only a 16-bit interface but run at higher speeds than DDR. To get maximum performance, Intel RDRAM chipsets require the use of RIMMs in pairs over a dual-channel 32-bit interface.