what id defrebt between ddr1 and ddr2 ram  

DDR1
Originally known as plain 'DDR', this type of memory has become less common over the years, having been virtually replaced by DDR2. It's an evolution of SDRAM with 184 pins. While SDRAM transfers data once per clock signal, DDR transfers data twice, almost doubling the data transfer rate. DDR is Double data rate (DDR) SDRAM.


DDR2
DDR2 is the most common type of memory in modern PCs today, having introduced features and functions that go well beyond the DDR SDRAM specification. It has 240 pins and is able to operate at data rates much faster than DDR1. Additionally, DDR2 adds a second port to transfer data packets to the CPU, doubling the transfer rate of DDR1.

Answered by Hem@nt .... at 3:17 PM on September 23, 2008

well;
In DDR1 the Chip is in Rectangle shape and DDR2 the Chip Shape is in Square

and DDR2 is Chip smaller than DDR1.DDR1 is centre cutting 7.5cm.DDR2 is centre

cutting 7cm.DDR1 pin 92. DD2 pin 122.DDR1 pin is larger than DDR2.

ddr1m has a functioning speed of max 400(337 mHz)

and ddr2 had a max of 800 mhz

Answered by Kishore at 8:46 AM on September 23, 2008

The difference between DDR1 and DDR2 are given below-

Feature/Option === DDR1 === DDR2 === DDR2 Advantage

Package ==TSOP (66 pins) === FBGA only ==Enables better electrical performance and speed
Voltage ==2.5V 2.5V I/O === 1.8V 1.8V I/O === Reduces memory system power demand

Densities === 128MB¨C1GB ==256MB¨C2GB == High-density components enable large memory subsystems

Internal Banks === 4 === 4 and 8 === 1GB and higher DDR2 devices will have 8 banks for better performance

Prefetch (MIN WRITE Burst) == 2 ==4 == Provides reduced core speed dependency for better yields

Speed (Data Pin) === 200 MHz,266 MHz,333 MHz,and400 MHz ===400 MHz,533 MHz,and667 Hz =====Migration to higher bus speed

READ Latency Additive Latency (Posted CAS) ==== 2, 2.5, 3 CLK N/A === CL + AL ,CL = 3, 4, 5,AL options 0, 1, 2, 3, 4 === Eliminating one-half clock settings helps speed internal DRAM logic and improves yields,Mainly used in server applications to improve command bus efficiency

WRITE Latency ==1 clock === READ latency - 1 ==== Improves command bus efficiency

Termination ==== Motherboard parallel to VTT===== DRAM on-die termination (ODT), optional onmotherboard termination === ODT for both memory and controller
improves signaling and reduces system cost

Data Strobes ==== Single-ended ==== Differential or single-ended ===Improves system timing margin by reducing strobe crosstalk

Modules ===== 184-pin DIMM unbuffered registered 200-pin SODIMM ,172-pin MicroDIMM === 240-pin DIMM unbuffered registered,200-pin SODIMM , 214-pin MicroDIMM === Improved layout and power delivery design

Chipset Support === All DTs, NBs, and servers ===All DTs, NBs, and servers === All major chipset providers

For more information-
http://www.merit line.com/compare-ddr2-with-ddr .html

Answered by Nagendra at 8:43 AM on September 23, 2008

well shashi,
DDR-2 is the latest generation of computer memory, which has evolved from DDR (or called DDR-1) memory. DDR-2 has several advantages over DDR-1, including higher speeds, lower power consumption, smaller physical sizes, and greater MB module sizes available. The parts are notched differently, meaning they are not interchangeable. If your system takes the older style DDR-1 memory, it cannot use the newer DDR-2 style memory.

DDR and DDR-2 memory are the newest benchmarks for computer memory today. Each run at different megahertz (MHz) speeds and are designed for optimal performance in the computer.
well other then this.
In DDR1 the Chip is in Rectangle shape and DDR2 the Chip Shape is in Square and DDR2 is Chip smaller than DDR1.DDR1 is centre cutting 7.5cm.DDR2 is centre cutting 7cm.DDR1 pin 92. DD2 pin 122.DDR1 pin is larger than DDR2.
and for detailed info;
http://hubpages.com/hub/DDR1 __DDR2__DDR3_Navigating_The_RAM_Maz e

Answered by Nz at 11:22 PM on September 22, 2008

Well, DDR2 (Double Data Rate) RAM is relatively a new type of RAM.

Following are the differences between DDR2 and DDR.

1) DDR2 is the next logical progression for memory standards and speeds. DDR2 incorporates several new designs and specifications which play a part in it's increased speed.

2) On-Die Termination: On-Die Termination is what it sounds like. With DDR, excess signal noise was eliminated by transistors built into the motherboard, but DDR2 has the terminating transistors built into each memory chip.

3) Posted CAS and Additive Latency: These two, prevent data collisions within the memory while still able to transfer more read/write instructions per clock cycle.

4) Off Chip Driver Calibration : DDR2 increases signal integrity than DDR.

5) Prefetch : DDR uses a 2-bit prefetch while DDR2 now uses a 4-bit prefetch.

6) Package : No, not the cardboard and plastic that the memory comes shipped in, but the packaging of the memory chips themselves. Using a Fine Ball Grid Array (FBGA), DDR2 can be made smaller than DDR which uses Thin Small Outline Package (TSOP).

For detailed information , Visit the source site :

http://www.meritline.com/com pa re-ddr2-with-ddr.html

Answered by Alok Gupta at 7:37 PM on September 22, 2008