Double Data Rate Synchronous Dynamic Random-Access Memory is a double data rate (DDR) synchronous dynamic random-access memory (SDRAM) class of memory integrated circuits used in computers. DDR SDRAM, also retroactively called DDR1 SDRAM, has been superseded by DDR2 SDRAM, DDR3 SDRAM, DDR4 SDRAM and DDR5 SDRAM. None of its successors are forward or backward compatible with DDR1 SDRAM, meaning DDR2, DDR3, DDR4 and DDR5 memory modules will not work on DDR1-equipped motherboards, and vice versa.
Synchronous dynamic random-access memory is any DRAM where the operation of its external pin interface is coordinated by an externally supplied clock signal.
A DIMM, or Dual In-Line Memory Module, is a popular type of memory module used in computers. It is a printed circuit board with one or both sides holding DRAM chips and pins. The vast majority of DIMMs are standardized through JEDEC standards, although there are proprietary DIMMs. DIMMs come in a variety of speeds and sizes, but generally are one of two lengths - PC which are 133.35 mm (5.25 in) and laptop (SO-DIMM) which are about half the size at 67.60 mm (2.66 in).
Rambus DRAM (RDRAM), and its successors Concurrent Rambus DRAM (CRDRAM) and Direct Rambus DRAM (DRDRAM), are types of synchronous dynamic random-access memory (SDRAM) developed by Rambus from the 1990s through to the early 2000s. The third-generation of Rambus DRAM, DRDRAM was replaced by XDR DRAM. Rambus DRAM was developed for high-bandwidth applications and was positioned by Rambus as replacement for various types of contemporary memories, such as SDRAM.
The Macintosh IIfx is a personal computer designed, manufactured and sold by Apple Computer from March 1990 to April 1992. At introduction it cost from US$9,000 to US$12,000, depending on configuration, and it was the fastest Macintosh available at the time.
Double Data Rate 2 Synchronous Dynamic Random-Access Memory is a double data rate (DDR) synchronous dynamic random-access memory (SDRAM) interface. It is a JEDEC standard (JESD79-2); first published in September 2003. DDR2 succeeded the original DDR SDRAM specification, and was itself succeeded by DDR3 SDRAM in 2007. DDR2 DIMMs are neither forward compatible with DDR3 nor backward compatible with DDR.
In computing, serial presence detect (SPD) is a standardized way to automatically access information about a memory module. Earlier 72-pin SIMMs included five pins that provided five bits of parallel presence detect (PPD) data, but the 168-pin DIMM standard changed to a serial presence detect to encode more information.
Double Data Rate 3 Synchronous Dynamic Random-Access Memory is a type of synchronous dynamic random-access memory (SDRAM) with a high bandwidth interface, and has been in use since 2007. It is the higher-speed successor to DDR and DDR2 and predecessor to DDR4 synchronous dynamic random-access memory (SDRAM) chips. DDR3 SDRAM is neither forward nor backward compatible with any earlier type of random-access memory (RAM) because of different signaling voltages, timings, and other factors.
RAM parity checking is the storing of a redundant parity bit representing the parity of a small amount of computer data stored in random-access memory, and the subsequent comparison of the stored and the computed parity to detect whether a data error has occurred.
The Apple Network Server (ANS) was a line of PowerPC-based server computers designed, manufactured and sold by Apple Computer, Inc. from February 1996 to April 1997. It was codenamed "Shiner" and originally consisted of two models, the Network Server 500/132 and the Network Server 700/150, which got a companion model, the Network Server 700/200 with a faster CPU in November 1996.
A Fully Buffered DIMM (FB-DIMM) is a type of memory module used in computer systems. It is designed to improve memory performance and capacity by allowing multiple memory modules to be each connected to the memory controller using a serial interface, rather than a parallel one. Unlike the parallel bus architecture of traditional DRAMs, an FB-DIMM has a serial interface between the memory controller and the advanced memory buffer (AMB). Conventionally, data lines from the memory controller have to be connected to data lines in every DRAM module, i.e. via multidrop buses. As the memory width increases together with the access speed, the signal degrades at the interface between the bus and the device. This limits the speed and memory density, so FB-DIMMs take a different approach to solve the problem.
A memory controller, also known as memory chip controller (MCC) or a memory controller unit (MCU), is a digital circuit that manages the flow of data going to and from a computer's main memory. When a memory controller is integrated into another chip, such as being placed on the same die or as an integral part of a microprocessor, it is usually called an integrated memory controller (IMC).
In computing, a memory module or RAM stick is a printed circuit board on which memory integrated circuits are mounted.
Double Data Rate 4 Synchronous Dynamic Random-Access Memory is a type of synchronous dynamic random-access memory with a high bandwidth interface.
A memory rank is a set of DRAM chips connected to the same chip select, which are therefore accessed simultaneously. In practice all DRAM chips share all of the other command and control signals, and only the chip select pins for each rank are separate.
In the design of modern computers, memory geometry describes the internal structure of random-access memory. Memory geometry is of concern to consumers upgrading their computers, since older memory controllers may not be compatible with later products. Memory geometry terminology can be confusing because of the number of overlapping terms.
Apollo VP3 is a x86 based Socket 7 chipset which was manufactured by VIA Technologies and was launched in 1997. On its time Apollo VP3 was a high performance, cost effective, and energy efficient chipset. It offered AGP support for Socket 7 processors which was not supported at that moment by Intel, SiS and ALi chipsets. In November 1997 FIC released motherboard PA-2012, which uses Apollo VP3 and has AGP bus. This was the first Socket 7 motherboard supporting AGP.
HyperCloud Memory (HCDIMM) is a DDR3 SDRAM dual in-line memory module (DIMM) used in server applications requiring a great deal of memory. It was initially launched in 2009 at the International Supercomputing Conference by Irvine, California, based company, Netlist Inc. It was never a JEDEC standard, and the main server vendors supporting it were IBM and Hewlett Packard Enterprise.
Double Data Rate 5 Synchronous Dynamic Random-Access Memory is the latest type of synchronous dynamic random-access memory. Compared to its predecessor DDR4 SDRAM, DDR5 was planned to reduce power consumption, while doubling bandwidth. The standard, originally targeted for 2018, was released on July 14, 2020.
UniDIMM is a specification for dual in-line memory modules (DIMMs), which are printed circuit boards (PCBs) designed to carry dynamic random-access memory (DRAM) chips. UniDIMMs can be populated with either DDR3 or DDR4 chips, with no support for any additional memory control logic; as a result, the computer's memory controller must support both DDR3 and DDR4 memory standards. The UniDIMM specification was created by Intel for its Skylake microarchitecture, whose integrated memory controller (IMC) supports both DDR3 and DDR4 memory technologies.
