Top 8 How Many Pins Does Ddr Sdram Have Quick Answer

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DDR SDRAM modules for desktop computers, dual in-line memory modules (DIMMs), have 184 pins (as opposed to 168 pins on SDRAM, or 240 pins on DDR2 SDRAM), and can be differentiated from SDRAM DIMMs by the number of notches (DDR SDRAM has one, SDRAM has two).Chips and modules

For use in computers, DDR2 SDRAM is supplied in DIMMs with 240 pins and a single locating notch.DDR2 SDRAM or Double Data Rate Synchronous Dynamic RAM

DDR2 SDRAM has 240 pins, which prevents backward compatibility with 168 pin DDR SDRAM.

Contents

How many pins a DDR2 SDRAM memory have?

Chips and modules

For use in computers, DDR2 SDRAM is supplied in DIMMs with 240 pins and a single locating notch.

Which DDR has 240 pins?

DDR2 SDRAM or Double Data Rate Synchronous Dynamic RAM

DDR2 SDRAM has 240 pins, which prevents backward compatibility with 168 pin DDR SDRAM.

How many pins are in DRAM?

The board has DRAMs mounted on both sides and is 168 pins.

How many pins are there on a DIMM stick of DDR4 SDRAM?

It differs from standard DIMM in that the DDR4 SO-DIMM has 260 pins versus 288 pins for the DRR4 DIMM. Standard DIMMs are used in PCs and servers.

How many pins does DDR3 SDRAM have?

DDR3 dual-inline memory modules (DIMMs) have 240 pins and are electrically incompatible with DDR2.

How many pins are in DDR3?

Physically, a DDR4 module, or dual in-line memory module (DIMM), looks very similar to a DDR3 DIMM. However, DDR4 has 288 pins compared with DDR3’s 240 pins; DDR4 SO-DIMMS have 260 pins instead of 204 in DDR3.

What RAM has 168 pins?

RAM Guide

Type	Pins	Total Module Size
1 x 64 DIMM	168	8MB
2 x 64 DIMM	168	16MB
4 x 64 DIMM	168	32MB
4 x 64 DIMM	168	32MB

17 thg 11, 1997

How many notches are on a SDRAM DIMM?

SDRAM was the first ram to be in sync with the system clock. So that you would know it is SDRAM it has 2 notches and 168-pins.

What is the difference between DDR4 and SDRAM?

The main difference between SDRAM and DDR memory is the doubled speed: DDR can transfer data at roughly twice the speed of SDRAM. PC133 SDRAM runs at 133 MHz, while 133 MHz DDR effectively runs at 133 MHz x 2 = 266 Mhz.

How many pins does a DRAM address have?

Rather, 64-bit DIMMs (Dual In-line Memory Modules) are the standard. These organize the memory 64-bits wide. The board has DRAMs mounted on both sides and is 168 pins.

How many pins does a DIMM have?

SDR (single data rate) DIMMs have 168 pins, one notch on either side, and two notches along the contact area. DDR (double data rate) DIMMs, on the other hand, have 184 pins, two notches on each side, and only one offset notch along the contact area.

How many pins are in DDR5?

DDR5 RAM sticks will have the same number of pins, 288, as DDR4 DRAM (opens in new tab) modules.

Is SDRAM and DIMM the same?

DIMM is a printed circuit board with mounted DRAM or SDRAM integrated circuits. SDRAM is Synchronous DRAM that runs at significantly higher clock speeds. Cooling. As DIMM chip density increased to improve performance, higher clock speeds generated more heat.

How do I know if my ram stick is DDR3 or DDR4?

Checking RAM type, once you know the speeds you’re supposed to be looking for, is very easy. Open Task Manager and go to the Performance tab. Select memory from the column on the left, and look at the very top right. It will tell you how much RAM you have and what type it is.

How many pins does my RAM have?

The 288 pins are in the normal DDR4 SDRAM, which is what you need.

What is DDR2 SDRAM in computer?

DDR2-SDRAM is a high-performance synchronous dynamic random-access memory interface. It is the successor to DDR-SDRAM. It offers new features, greater bandwidth and lesser power consumption than its predecessor. DDR2-SDRAM was succeeded by DDR3-SDRAM.

How many pins DIMM have?

How many pins does my motherboard have for RAM?

Distinguished. It supports DDR4 in dual channel in a variety of speeds… which is 288 pins.

RAM: SDRAM (SDR) vs DDR (SDRAM) – How much quicker is DDR?

DDR SDRAM – Wikipedia

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Table of Contents:

Contents

History[edit]

Specification[edit]

Generations[edit]

DDR SDRAM

Type of computer memory

This article is about DDR SDRAM. For graphics DDR, see GDDR

Double Data Rate Synchronous Dynamic Random-Access Memory (DDR SDRAM) 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 in DDR1-equipped motherboards, and vice versa.

Compared to single data rate (SDR) SDRAM, the DDR SDRAM interface makes higher transfer rates possible by more strict control of the timing of the electrical data and clock signals. Implementations often have to use schemes such as phase-locked loops and self-calibration to reach the required timing accuracy.[4][5] The interface uses double pumping (transferring data on both the rising and falling edges of the clock signal) to double data bus bandwidth without a corresponding increase in clock frequency. One advantage of keeping the clock frequency down is that it reduces the signal integrity requirements on the circuit board connecting the memory to the controller. The name “double data rate” refers to the fact that a DDR SDRAM with a certain clock frequency achieves nearly twice the bandwidth of a SDR SDRAM running at the same clock frequency, due to this double pumping.

With data being transferred 64 bits at a time, DDR SDRAM gives a transfer rate (in bytes/s) of (memory bus clock rate) × 2 (for dual rate) × 64 (number of bits transferred) / 8 (number of bits/byte). Thus, with a bus frequency of 100 MHz, DDR SDRAM gives a maximum transfer rate of 1600 MB/s.

History [ edit ]
A Samsung DDR SDRAM 64MBit chip

In the late 1980s IBM had built DRAMs using a dual-edge clocking feature and presented their results in the International Solid-State Circuits Convention in 1990.[6][7]
Samsung demonstrated the first DDR memory prototype in 1997,[1] and released the first commercial DDR SDRAM chip (64 Mb) in June 1998,[8][2][3] followed soon after by Hyundai Electronics (now SK Hynix) the same year.[9] The development of DDR began in 1996, before its specification was finalized by JEDEC in June 2000 (JESD79).[10] JEDEC has set standards for data rates of DDR SDRAM, divided into two parts. The first specification is for memory chips, and the second is for memory modules. The first retail PC motherboard using DDR SDRAM was released in August 2000.[11]
Specification [ edit ]
Single generic DDR memory module

4 DDR RAM slots

Corsair DDR-400 memory with heat spreaders

Physical DDR layout

Comparison of memory modules for portable/mobile PCs ( SO-DIMM ).

Modules [ edit ]
To increase memory capacity and bandwidth, chips are combined on a module. For instance, the 64-bit data bus for DIMM requires eight 8-bit chips, addressed in parallel. Multiple chips with the common address lines are called a memory rank. The term was introduced to avoid confusion with chip internal rows and banks. A memory module may bear more than one rank. The term sides would also be confusing because it incorrectly suggests the physical placement of chips on the module. All ranks are connected to the same memory bus (address + data). The chip select signal is used to issue commands to specific rank.

Adding modules to the single memory bus creates additional electrical load on its drivers. To mitigate the resulting bus signaling rate drop and overcome the memory bottleneck, new chipsets employ the multi-channel architecture.

Comparison of DDR SDRAM standards Name Chip Bus Timings Voltage V) Standard Type Module Clock rate MHz) Cycle time ns) [12] Clock rate (MHz) Transfer rate (MT/s) Bandwidth (MB/s) CL-T RCD -T RP CAS latency (ns) DDR-200 PC-1600 100 10 100 200 1600 2-2-2 20 2.5±0.2 DDR-266 PC-2100 133⅓ 7.5 133⅓ 266.67 2133⅓ 2.5-3-3 18.75 DDR-333 PC-2700 166⅔ 6 166⅔ 333⅓ 2666⅔ 2.5-3-3 15 DDR-400 A PC-3200 200 5 200 400 3200 2.5-3-3 12.5 2.6±0.1 B 3-3-3 15 C 3-4-4 15

Note: All above listed are specified by JEDEC as JESD79F.[13] All RAM data rates in-between or above these listed specifications are not standardized by JEDEC — often they are simply manufacturer optimizations using tighter-tolerance or overvolted chips. The package sizes in which DDR SDRAM is manufactured are also standardized by JEDEC.

There is no architectural difference between DDR SDRAM modules. Modules are instead designed to run at different clock frequencies: for example, a PC-1600 module is designed to run at 100 MHz, and a PC-2100 is designed to run at 133 MHz. A module’s clock speed designates the data rate at which it is guaranteed to perform, hence it is guaranteed to run at lower (underclocking) and can possibly run at higher (overclocking) clock rates than those for which it was made.[14]
DDR SDRAM modules for desktop computers, dual in-line memory modules (DIMMs), have 184 pins (as opposed to 168 pins on SDRAM, or 240 pins on DDR2 SDRAM), and can be differentiated from SDRAM DIMMs by the number of notches (DDR SDRAM has one, SDRAM has two). DDR SDRAM for notebook computers, SO-DIMMs, have 200 pins, which is the same number of pins as DDR2 SO-DIMMs. These two specifications are notched very similarly and care must be taken during insertion if unsure of a correct match. Most DDR SDRAM operates at a voltage of 2.5 V, compared to 3.3 V for SDRAM. This can significantly reduce power consumption. Chips and modules with DDR-400/PC-3200 standard have a nominal voltage of 2.6 V.

JEDEC Standard No. 21–C defines three possible operating voltages for 184 pin DDR, as identified by the key notch position relative to its centreline. Page 4.5.10-7 defines 2.5V (left), 1.8V (centre), TBD (right), while page 4.20.5–40 nominates 3.3V for the right notch position. The orientation of the module for determining the key notch position is with 52 contact positions to the left and 40 contact positions to the right.

Increasing operating voltage slightly can increase maximum speed, at the cost of higher power dissipation and heating, and at the risk of malfunctioning or damage.

Capacity Number of DRAM devices The number of chips is a multiple of 8 for non-ECC modules and a multiple of 9 for ECC modules. Chips can occupy one side (single sided) or both sides (dual sided) of the module. The maximal number of chips per DDR module is 36 (9×4) for ECC and 32 (8×4) for non-ECC. ECC vs non-ECC Modules that have error-correcting code are labeled as ECC. Modules without error correcting code are labeled non-ECC. Timings CAS latency (CL), clock cycle time (t CK ), row cycle time (t RC ), refresh row cycle time (t RFC ), row active time (t RAS ). Buffering Registered (or buffered) vs unbuffered. Packaging Typically DIMM or SO-DIMM. Power consumption A test with DDR and DDR2 RAM in 2005 found that average power consumption appeared to be of the order of 1–3 W per 512 MB module; this increases with clock rate and when in use rather than idling.[15] A manufacturer has produced calculators to estimate the power used by various types of RAM.[16]
Module and chip characteristics are inherently linked.

Total module capacity is a product of one chip’s capacity and the number of chips. ECC modules multiply it by 8/9 because they use 1 bit per byte (8 bits) for error correction. A module of any particular size can therefore be assembled either from 32 small chips (36 for ECC memory), or 16(18) or 8(9) bigger ones.

DDR memory bus width per channel is 64 bits (72 for ECC memory). Total module bit width is a product of bits per chip and number of chips. It also equals number of ranks (rows) multiplied by DDR memory bus width. Consequently, a module with a greater number of chips or using ×8 chips instead of ×4 will have more ranks.

Example: Variations of 1 GB PC2100 registered DDR SDRAM module with ECC Module size (GB) Number of chips Chip size (Mbit) Chip organization Number of ranks 1 36 256 64M×4 2 1 18 512 64M×8 2 1 18 512 128M×4 1

This example compares different real-world server memory modules with a common size of 1 GB. One should definitely be careful buying 1 GB memory modules, because all these variations can be sold under one price position without stating whether they are ×4 or ×8, single- or dual-ranked.

There is a common belief that number of module ranks equals number of sides. As above data shows, this is not true. One can also find 2-side/1-rank modules. One can even think of a 1-side/2-rank memory module having 16(18) chips on single side ×8 each, but it’s unlikely such a module was ever produced.

Chip characteristics [ edit ]
The die of a Samsung DDR-SDRAM 64MBit package

DRAM density Size of the chip is measured in megabits. Most motherboards recognize only 1 GB modules if they contain 64M×8 chips (low density). If 128M×4 (high density) 1 GB modules are used, they most likely will not work. The JEDEC standard allows 128M×4 only for registered modules designed specifically for servers, but some generic manufacturers do not comply.[17][ verification needed ] Organization The notation like 64M×4 means that the memory matrix has 64 million (the product of banks x rows x columns) 4-bit storage locations. There are ×4, ×8, and ×16 DDR chips. The ×4 chips allow the use of advanced error correction features like Chipkill, memory scrubbing and Intel SDDC in server environments, while the ×8 and ×16 chips are somewhat less expensive. x8 chips are mainly used in desktops/notebooks but are making entry into the server market. There are normally 4 banks and only one row can be active in each bank.

Double data rate (DDR) SDRAM specification [ edit ]
From Ballot JCB-99-70, and modified by numerous other Board Ballots, formulated under the cognizance of Committee JC-42.3 on DRAM Parametrics.

Standard No. 79 Revision Log:

Release 1, June 2000

Release 2, May 2002

Release C, March 2003 – JEDEC Standard No. 79C.[18]
“This comprehensive standard defines all required aspects of 64Mb through 1Gb DDR SDRAMs with X4/X8/X16 data interfaces, including features, functionality, ac and dc parametrics, packages and pin assignments. This scope will subsequently be expanded to formally apply to x32 devices, and higher density devices as well.”

Organization [ edit ]
PC3200 is DDR SDRAM designed to operate at 200 MHz using DDR-400 chips with a bandwidth of 3,200 MB/s. Because PC3200 memory transfers data on both the rising and falling clock edges, its effective clock rate is 400 MHz.

1 GB PC3200 non-ECC modules are usually made with 16 512 Mbit chips, 8 on each side (512 Mbits × 16 chips) / (8 bits (per byte)) = 1,024 MB. The individual chips making up a 1 GB memory module are usually organized as 226 8-bit words, commonly expressed as 64M×8. Memory manufactured in this way is low-density RAM and is usually compatible with any motherboard specifying PC3200 DDR-400 memory.[19][citation needed]
Generations [ edit ]
DDR (DDR1) was superseded by DDR2 SDRAM, which had modifications for higher clock frequency and again doubled throughput, but operates on the same principle as DDR. Competing with DDR2 was Rambus XDR DRAM. DDR2 dominated due to cost and support factors. DDR2 was in turn superseded by DDR3 SDRAM, which offered higher performance for increased bus speeds and new features. DDR3 has been superseded by DDR4 SDRAM, which was first produced in 2011 and whose standards were still in flux (2012) with significant architectural changes.

DDR’s prefetch buffer depth is 2 (bits), while DDR2 uses 4. Although the effective clock rates of DDR2 are higher than DDR, the overall performance was not greater in the early implementations, primarily due to the high latencies of the first DDR2 modules. DDR2 started to be effective by the end of 2004, as modules with lower latencies became available.[20]
Memory manufacturers stated that it was impractical to mass-produce DDR1 memory with effective transfer rates in excess of 400 MHz (i.e. 400 MT/s and 200 MHz external clock) due to internal speed limitations. DDR2 picks up where DDR1 leaves off, utilizing internal clock rates similar to DDR1, but is available at effective transfer rates of 400 MHz and higher. DDR3 advances extended the ability to preserve internal clock rates while providing higher effective transfer rates by again doubling the prefetch depth.

The DDR4 SDRAM is a high-speed dynamic random-access memory internally configured as 16 banks, 4 bank groups with 4 banks for each bank group for x4/x8 and 8 banks, 2 bank groups with 4 banks for each bank group for x16 DRAM. The DDR4 SDRAM uses an 8n prefetch architecture to achieve high-speed operation. The 8n prefetch architecture is combined with an interface designed to transfer two data words per clock cycle at the I/O pins. A single read or write operation for the DDR4 SDRAM consists of a single 8n-bit-wide 4-clock data transfer at the internal DRAM core and 8 corresponding n-bit-wide half-clock-cycle data transfers at the I/O pins.[21]
RDRAM was a particularly expensive alternative to DDR SDRAM, and most manufacturers dropped its support from their chipsets. DDR1 memory’s prices substantially increased since Q2 2008, while DDR2 prices declined. In January 2009, 1 GB DDR1 was 2–3 times more expensive than 1 GB DDR2.[citation needed]
Comparison of DDR SDRAM generations Name Release

year Chip Bus Voltage

(V) Pins Gen Standard Clock rate

(MHz) Cycle time

(ns) Pre-

fetch Clock rate

(MHz) Transfer rate

(MT/s) Bandwidth

(MB/s) DIMM SO-

DIMM Micro-

DIMM DDR DDR-200 1998 100 10 2n 100 200 1600 2.5 184 200 172 DDR-266 133 7.5 133 266 2133⅓ DDR-333 166⅔ 6 166⅔ 333 2666⅔ DDR-400 200 5 200 400 3200 2.6 DDR2 DDR2-400 2003 100 10 4n 200 400 3200 1.8 240 200 214 DDR2-533 133⅓ 7.5 266⅔ 533⅓ 4266⅔ DDR2-667 166⅔ 6 333⅓ 666⅔ 5333⅓ DDR2-800 200 5 400 800 6400 DDR2-1066 266⅔ 3.75 533⅓ 1066⅔ 8533⅓ DDR3 DDR3-800 2007 100 10 8n 400 800 6400 1.5/1.35 240 204 214 DDR3-1066 133⅓ 7.5 533⅓ 1066⅔ 8533⅓ DDR3-1333 166⅔ 6 666⅔ 1333⅓ 10666⅔ DDR3-1600 200 5 800 1600 12800 DDR3-1866 233⅓ 4.29 933⅓ 1866⅔ 14933⅓ DDR3-2133 266⅔ 3.75 1066⅔ 2133⅓ 17066⅔ DDR4 DDR4-1600 2014 200 5 8n 800 1600 12800 1.2/1.05 288 260 – DDR4-1866 233⅓ 4.29 933⅓ 1866⅔ 14933⅓ DDR4-2133 266⅔ 3.75 1066⅔ 2133⅓ 17066⅔ DDR4-2400 300 3⅓ 1200 2400 19200 DDR4-2666 333⅓ 3 1333⅓ 2666⅔ 21333⅓ DDR4-2933 366⅔ 2.73 1466⅔ 2933⅓ 23466⅔ DDR4-3200 400 2.5 1600 3200 25600 DDR5 DDR5-3200 2020 200 5 16n 1600 3200 25600 1.1 288 262 DDR5-3600 225 4.44 1800 3600 28800 DDR5-4000 250 4 2000 4000 32000 DDR5-4800 300 3⅓ 2400 4800 38400 DDR5-5000 312½ 3.2 2500 5000 40000 DDR5-5120 320 3⅛ 2560 5120 40960 DDR5-5333 333⅓ 3 2666⅔ 5333⅓ 42666⅔ DDR5-5600 350 2.86 2800 5600 44800 DDR5-6400 400 2.5 3200 6400 51200 DDR5-7200 450 2.22 3600 7200 57600

Mobile DDR [ edit ]
MDDR is an acronym that some enterprises use for Mobile DDR SDRAM, a type of memory used in some portable electronic devices, like mobile phones, handhelds, and digital audio players. Through techniques including reduced voltage supply and advanced refresh options, Mobile DDR can achieve greater power efficiency.

See also [ edit ]

DDR2 SDRAM

Second generation of double-data-rate synchronous dynamic random-access memory

Double Data Rate 2 Synchronous Dynamic Random-Access Memory (DDR2 SDRAM) is a double data rate (DDR) synchronous dynamic random-access memory (SDRAM) interface. It superseded the original DDR SDRAM specification, and was itself superseded by DDR3 SDRAM (launched in 2007). DDR2 DIMMs are neither forward compatible with DDR3 nor backward compatible with DDR.

In addition to double pumping the data bus as in DDR SDRAM (transferring data on the rising and falling edges of the bus clock signal), DDR2 allows higher bus speed and requires lower power by running the internal clock at half the speed of the data bus. The two factors combine to produce a total of four data transfers per internal clock cycle.

Since the DDR2 internal clock runs at half the DDR external clock rate, DDR2 memory operating at the same external data bus clock rate as DDR results in DDR2 being able to provide the same bandwidth but with better latency. Alternatively, DDR2 memory operating at twice the external data bus clock rate as DDR may provide twice the bandwidth with the same latency. The best-rated DDR2 memory modules are at least twice as fast as the best-rated DDR memory modules. The maximum capacity on commercially available DDR2 DIMMs is 8GB, but chipset support and availability for those DIMMs is sparse and more common 2GB per DIMM are used.[citation needed][2]
History [ edit ]
DDR2 SDRAM was first produced by Samsung in 2001. In 2003, the JEDEC standards organization presented Samsung with its Technical Recognition Award for the company’s efforts in developing and standardizing DDR2.[1]
DDR2 was officially introduced in the second quarter of 2003 at two initial clock rates: 200 MHz (referred to as PC2-3200) and 266 MHz (PC2-4200). Both performed worse than the original DDR specification due to higher latency, which made total access times longer. However, the original DDR technology tops out at a clock rate around 200 MHz (400 MT/s). Higher performance DDR chips exist, but JEDEC has stated that they will not be standardized. These chips are mostly standard DDR chips that have been tested and rated to be capable of operation at higher clock rates by the manufacturer. Such chips draw significantly more power than slower-clocked chips, but usually offered little or no improvement in real-world performance. DDR2 started to become competitive against the older DDR standard by the end of 2004, as modules with lower latencies became available.[3]
Specification [ edit ]
Overview [ edit ]
PC2-5300 DDR2 SO-DIMM (for notebooks)

Comparison of memory modules for desktop PCs (DIMM)

Comparison of memory modules for portable/mobile PCs (SO-DIMM)

The key difference between DDR2 and DDR SDRAM is the increase in prefetch length. In DDR SDRAM, the prefetch length was two bits for every bit in a word; whereas it is four bits in DDR2 SDRAM. During an access, four bits were read or written to or from a four-bit-deep prefetch queue. This queue received or transmitted its data over the data bus in two data bus clock cycles (each clock cycle transferred two bits of data). Increasing the prefetch length allowed DDR2 SDRAM to double the rate at which data could be transferred over the data bus without a corresponding doubling in the rate at which the DRAM array could be accessed. DDR2 SDRAM was designed with such a scheme to avoid an excessive increase in power consumption.

DDR2’s bus frequency is boosted by electrical interface improvements, on-die termination, prefetch buffers and off-chip drivers. However, latency is greatly increased as a trade-off. The DDR2 prefetch buffer is four bits deep, whereas it is two bits deep for DDR. While DDR SDRAM has typical read latencies of between two and three bus cycles, DDR2 may have read latencies between three and nine cycles, although the typical range is between four and six. Thus, DDR2 memory must be operated at twice the data rate to achieve the same latency.

Another cost of the increased bandwidth is the requirement that the chips are packaged in a more expensive and difficult to assemble BGA package as compared to the TSSOP package of the previous memory generations such as DDR SDRAM and SDR SDRAM. This packaging change was necessary to maintain signal integrity at higher bus speeds.

Power savings are achieved primarily due to an improved manufacturing process through die shrinkage, resulting in a drop in operating voltage (1.8 V compared to DDR’s 2.5 V). The lower memory clock frequency may also enable power reductions in applications that do not require the highest available data rates.

According to JEDEC[4] the maximum recommended voltage is 1.9 volts and should be considered the absolute maximum when memory stability is an issue (such as in servers or other mission critical devices). In addition, JEDEC states that memory modules must withstand up to 2.3 volts before incurring permanent damage (although they may not actually function correctly at that level).

Chips and modules [ edit ]
For use in computers, DDR2 SDRAM is supplied in DIMMs with 240 pins and a single locating notch. Laptop DDR2 SO-DIMMs have 200 pins and often come identified by an additional S in their designation. DIMMs are identified by their peak transfer capacity (often called bandwidth).

Comparison of DDR2 SDRAM standards Name Chip Bus Timings Standard Type Module Clock rate MHz) Cycle time ns) [5] Clock rate (MHz) Transfer rate (MT/s) Bandwidth (MB/s) CL-T RCD -T RP [6][7] CAS latency (ns) DDR2-400 B PC2-3200 100 10 200 400 3200 3-3-3 15 C 4-4-4 20 DDR2-533 B PC2-4200* 133 7.5 266 533 4266 3-3-3 11.25 C 4-4-4 15 DDR2-667 C PC2-5300* 166 6 333 667 5333 4-4-4 12 D 5-5-5 15 DDR2-800 C PC2-6400 200 5 400 800 6400 4-4-4 10 D 5-5-5 12.5 E 6-6-6 15 DDR2-1066 E PC2-8500* 266 3.75 533 1066 8533 6-6-6 11.25 F 7-7-7 13.125

Relative speed comparison between similar modules PC-5300 PC-6400 5-5-5 4-4-4 6-6-6 5-5-5 4-4-4 PC2-3200 4-4-4 % % +33% +60% % PC2-3200 3-3-3 % % = +20% % PC2-4200 4-4-4 % % = +21% % PC2-4200 3-3-3 % % −24% −9% % PC2-5300 5-5-5 % % = +21% % PC2-5300 4-4-4 % % −19% −3% % PC2-6400 6-6-6 % % = +20% % PC2-6400 5-5-5 % % −16% = % PC2-6400 4-4-4 % % −33% −20% % PC2-8500 7-7-7 % % −12% +6% % PC2-8500 6-6-6 % % −25% −9% %

* Some manufacturers label their DDR2 modules as PC2-4300, PC2-5400 or PC2-8600 instead of the respective names suggested by JEDEC. At least one manufacturer has reported this reflects successful testing at a higher-than-standard data rate[8] whilst others simply round up for the name.

Note: DDR2-xxx denotes data transfer rate, and describes raw DDR chips, whereas PC2-xxxx denotes theoretical bandwidth (with the last two digits truncated), and is used to describe assembled DIMMs. Bandwidth is calculated by taking transfers per second and multiplying by eight. This is because DDR2 memory modules transfer data on a bus that is 64 data bits wide, and since a byte comprises 8 bits, this equates to 8 bytes of data per transfer.

P vs F Server DIMM’s Notch Positions compared DDR2vsDIMM’s Notch Positions compared

In addition to bandwidth and capacity variants, modules can:

Optionally implement ECC, which is an extra data byte lane used for correcting minor errors and detecting major errors for better reliability. Modules with ECC are identified by an additional ECC in their designation. PC2-4200 ECC is a PC2-4200 module with ECC. An additional P can be added at the end of the designation, P standing for parity (ex : PC2-5300P). Intel ® 6402 Advanced Memory Buffer R in their designation, whereas non-registered (a.k.a. “unbuffered”) RAM may be identified by an additional U in the designation. PC2-4200R is a registered PC2-4200 module, PC2-4200R ECC is the same module but with additional ECC. Be aware fully buffered modules, which are designated by F or FB do not have the same notch position as other classes. Fully buffered modules cannot be used with motherboards that are made for registered modules, and the different notch position physically prevents their insertion.

Note:

Registered and un-buffered SDRAM generally cannot be mixed on the same channel.

The highest-rated DDR2 modules in 2009 operate at 533 MHz (1066 MT/s), compared to the highest-rated DDR modules operating at 200 MHz (400 MT/s). At the same time, the CAS latency of 11.2 ns = 6 / (bus clock rate) for the best PC2-8500 modules is comparable to that of 10 ns = 4 / (bus clock rate) for the best PC-3200 modules.

Backward compatibility [ edit ]
DDR2 DIMMs are not backward compatible with DDR DIMMs. The notch on DDR2 DIMMs is in a different position from DDR DIMMs, and the pin density is higher than DDR DIMMs in desktops. DDR2 is a 240-pin module, DDR is a 184-pin module. Notebooks have 200-pin SO-DIMMs for DDR and DDR2; however, the notch on DDR2 modules is in a slightly different position than on DDR modules.

Higher-speed DDR2 DIMMs can be mixed with lower-speed DDR2 DIMMs, although the memory controller will operate all DIMMs at same speed as the lowest-speed DIMM present.

Relation to GDDR memory [ edit ]
GDDR2, a form of GDDR SDRAM, was developed by Samsung and introduced in July 2002.[9] The first commercial product to claim using the “DDR2” technology was the Nvidia GeForce FX 5800 graphics card. However, it is important to note that this GDDR2 memory used on graphics cards is not DDR2 per se, but rather an early midpoint between DDR and DDR2 technologies. Using “DDR2” to refer to GDDR2 is a colloquial misnomer. In particular, the performance-enhancing doubling of the I/O clock rate is missing. It had severe overheating issues due to the nominal DDR voltages. ATI has since designed the GDDR technology further into GDDR3, which is based on DDR2 SDRAM, though with several additions suited for graphics cards.

GDDR3 and GDDR5 is now commonly used in modern graphics cards and some tablet PCs. However, further confusion has been added to the mix with the appearance of budget and mid-range graphics cards which claim to use “GDDR2”. These cards actually use standard DDR2 chips designed for use as main system memory although operating with higher latencies to achieve higher clockrates. These chips cannot achieve the clock rates of GDDR3 but are inexpensive and fast enough to be used as memory on mid-range cards.

See also [ edit ]
References [ edit ]
Further reading [ edit ]
Note**: JEDEC website requires registration ($2,500 membership) for viewing or downloading of these documents: http://www.jedec.org/standards-documents

Types of RAM Used In Computers

All computing devices like laptops, desktop computers, smartphones, tablets and gaming systems are equipped with RAM. You will find below information about different types of RAM used in computers.

Types of RAM Used in Computers

RAM which is an acronym for “Random Access Memory” is basically designed to provide computers with an easy to access location for temporary storage of data required for running programs, executing processes and managing information.

The storage capacity of RAM is expressed in MB or GB (Mega & Giga Bytes) and the data processing speed of RAM is measured in MHz or GHz (Mega and Giga Hertz).

In general, you need to remember the following guidelines while going for an upgrade of RAM on your computer.

Laptop RAM is smaller (lesser pins) compared to Desktop RAM. Older generation computers cannot be upgraded with more recent types of RAM. RAM is not backward compatible. Different types of RAM cannot be mixed and matched on the same system.

While RAM basically serves the purpose of storing temporary information required by the computer for processing information, there are different types of RAM used in computers.

1. SRAM or Static RAM

This type of RAM is defined as “static” or SRAM because it does not need to be refreshed in order to remember or retain its Data.

SRAM retains Data only as long as it is supplied with constant Power supply. Once, the power supply is switched OFF, all the Data in SRAM gets erased or lost.

While SRAM uses less power and provides faster access to data, it offers less storage capacity and is expensive compared to DRAM.

SRAM is typically used in CPU Cache (L1, L2, L3), Hard Drive Cache and Video Cards. It is also used in Digital Cameras, Printers and routers.

2. DRAM or Dynamic RAM

This type of RAM functions by periodically refreshing its Data, due to which it is known as Dynamic type of memory.

Similar to SRAM, DRAM needs to be supplied with power and loses all its Data when the power supply is cutoff.

While DRAM is cheaper to manufacture and offers higher storage capacity, it offers slower access to Data and consumes more power compared to SRAM.

DRAM is used in System Memory and Video graphics memory of computers. It is also used in Video game consoles and networking hardware.

3. SDRAM or Synchronous Dynamic RAM

SDRAM can be defined as an improved type of DRAM designed to operate in sync with the CPU clock of the computer.

While SDRAM waits for clock signal from the computer before responding to Data input, it responds almost immediately (synchronously) to Data input.

The synchronous operating capacity of SDRAM allows it to process instructions in parallel, which is known as ‘pipelining’ or the ability to receive a new instruction, while the previous instruction is still being processed.

Since, pipelining allows more instructions to be simultaneously processed, it results in better or higher overall CPU performance.

4. SDR SDRAM or Single Data Rate Synchronous Dynamic RAM

SDR SDRAM is a first generation SDRAM that can process one read and one write instruction per clock cycle.

This type of RAM is used as Computer memory and used in Video game consoles.

5. DDR SDRAM or Double Data Rate Synchronous Dynamic RAM

DDR SDRAM is a second generation SDRAM that can process two read and two write instructions per clock cycle.

This makes DDR SDRAM twice as fast as SDR SDRAM while operating at a lower standard voltage (2.5 Volts compared to 3.3 volts).

DDR SDRAM has 184 pins and a single notch on the connector, compared 168 pins and two notches as found on SDR SDRAM.

DDR SDRAM is used in mid-range laptops and desktop computers.

6. DDR2 SDRAM or Double Data Rate Synchronous Dynamic RAM

This is an improved type of DDR SDRAM capable of providing double data rate transfer at higher clock speeds, compared to DDR SDRAM.

Typically, a standard (Not over clocked) DDR SDRAM can reach up to 200 MHz speed, while a standard DDR2 SDRAM can reach speeds of 533 MHz.

In terms of power consumption, DDR2 SDRAM runs at a lower voltage (1.8 V) compared to DDR 2.5 Volts required by SDRAM.

DDR2 SDRAM has 240 pins, which prevents backward compatibility with 168 pin DDR SDRAM.

7. DDR3 SDRAM or Triple Data Rate Synchronous Dynamic RAM

DDR3 SDRAM offers advanced signal processing, greater storage capacity, lower power consumption (1.5 V) and higher standard clock speeds of up to 800 MHz.

Although DDR3 SDRAM has the same number of pins as DDR2 SDRAM (240), it is still not backward compatible with DDR2.

8. DDR4 SDRAM

This improved type of SDRAM provides advanced signal processing, higher storage capacity, lower power consumption (1.2 V) and higher standard clock speeds (up to 1600 MHz).

DDR4 SDRAM uses 288-pin configuration, which prevents backward compatibility.

9. GDDR SDRAM – Graphics Double Data Rate Synchronous Dynamic RAM

GDDR SDRAM is a type of DDR SDRAM that has been specifically designed to provide advanced video graphics rendering, especially when combined with a dedicated GPU (Graphics Processing Unit).

Similar to DDR SDRAM, GDDR SDRAM has its own line of improved products that offer much improved graphic processing at lower power supply.

The improving or evolutionary GDDR SDRAM are labelled as GDDR2 SDRAM, GDDR3 SDRAM, GDDR4 SDRAM, and GDDR5 SDRAM.

This type of RAM is used in the video graphics card on Gaming computers and certain tablets.

While GDDR SDRAM provides comparatively slower data transfer, it is capable of handling large amounts of data.

10. Flash Memory

This is a basic type of memory which is more similar to the Hard Drive on computers than RAM.

Unlike RAM, Flash memory retains all its data, even after the power supply is cut off.

Hence, Flash memory is used in USB flash drives, Memory Cards, Portable Media players, PDAs and electronic toys.

So you have finished reading the how many pins does ddr sdram have topic article, if you find this article useful, please share it. Thank you very much. See more: how many pins does ddr have, DDR5, how many pins does ddr1 have, Double data rate, how many pins does ddr2 have, DDR protocol, Ddr SDRAM là gì, DDR5 release date

Top 8 How Many Pins Does Ddr Sdram Have Quick Answer

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