Friday, July 6, 2012

The various types of RAM on a PC

The various types of RAM on a PC
- DRAM (Dynamic RAM) is a type of RAM must be periodically refreshed by the CPU so that the data contained therein is not lost. Dynamic random-access memory (DRAM) is a type of random-access memory that stores each bit of data in a separate capacitor within an integrated circuit. The capacitor can be either charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1. Since capacitors leak charge, the information eventually fades unless the capacitor charge is refreshed. Because of this refresh requirement, it is a dynamic memory as opposed to SRAM and other static memory.

- SDRAM (Sync hronous Dynamic RAM) is the most common type of RAM used in PCs today. RAM is synchronized by the clock system, and has more speed than the DRAM tanggi. Suitable for systems with a bus that has the speed to 100 MHz. Synchronous dynamic random access memory (SDRAM) is dynamic random access memory (DRAM) that is synchronized with the system bus. Classic DRAM has an asynchronous interface, which means that it responds as quickly as possible to changes in control inputs. SDRAM has a synchronous interface, meaning that it waits for a clock signal before responding to control inputs and is therefore synchronized with the computer's system bus. The clock is used to drive an internal finite state machine that pipelines incoming commands. This allows the chip to have a more complex pattern of operation than an asynchronous DRAM, enabling higher speeds.

- SRAM (Static RAM) is a type of memory that does not need a refresher by the CPU, so that the data contained therein remain well. This type of RAM has a speed higher than the DRAM. Static random-access memory (SRAM) is a type of semiconductor memory that uses bistable latching circuitry to store each bit. The term static differentiates it from dynamic RAM (DRAM) which must be periodically refreshed. SRAM exhibits data remanence, but is still volatile in the conventional sense that data is eventually lost when the memory is not powered.

- RDRAM (Rambus Dynamic RAM) is a type of memory that is faster and more expensive than SDRAM. Memory can be used on systems that use the Pentium 4. Direct Rambus DRAM or DRDRAM (sometimes just called Rambus DRAM or RDRAM) is a type of synchronous dynamic RAM. RDRAM was developed by Rambus inc., in the mid-1990s as a replacement for then-prevalent DIMM SDRAM memory architecture. RDRAM was initially expected to become the standard in PC memory, especially after Intel agreed to license the Rambus technology for use with its future chipsets. Further, RDRAM was expected to become a standard for VRAM. However, RDRAM got embroiled in a standards war with an alternative technology - DDR SDRAM, quickly losing out on grounds of price, and, later on, performance. By the early 2000s, RDRAM was no longer supported by any mainstream computing architecture.

- EDO RAM (Extended Data Out RAM) is a type of memory used in systems that use the Pentium. Suitable for having a bus with speeds up to 66 MHz. EDO DRAM, sometimes referred to as Hyper Page Mode enabled DRAM, is similar to Fast Page Mode DRAM with the additional feature that a new access cycle can be started while keeping the data output of the previous cycle active. This allows a certain amount of overlap in operation (pipelining), allowing somewhat improved performance. It was 5% faster than FPM DRAM, which it began to replace in 1995, when Intel introduced the 430FX chipset that supported EDO DRAM.

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