DDR2 vs DDR1: Difference and Comparison

The abbreviation for Synchronous Dynamic Random-Access memory is SDRAM. It can be clear by its name that it has synchronous behaviour and synchronizes itself with the clock signal on CPU timing.

SDRAM can be divided into two types, viz. DDR SDRAM and SDR SDRAM.  

In this article, DDR SDRAM with its two versions is highlighted. The two versions are DDR2 and DDR1, in which DDR stands for Double Data Rate.

To service the computer then, it becomes important to know the difference between DDR2 and DDR1.  

Key Takeaways

1. DDR2 has a higher bandwidth than DDR1.
2. DDR2 is more power-efficient than DDR1.
3. DDR2 is more expensive than DDR1.

DDR2 vs DDR1 

The difference between DDR2 (Double Data Rate Version 2) and DDR1 (Double Data Rate) is that in DDR2 clock’s bus speed is twice that of the memory cells. Consequently, four words of data can transfer per memory cell cycle without speeding up the memory cells. DDR2 can operate the bus speed at twice as compared to DDR1.  

The abbreviation for Double Data Rate Version 2 is DDR2. This RAM version was developed to attain a high data rate for transferring the block.

DDR2 replaced the older version DDR1, where the main changes were made to the operational frequency between the prefetch buffer and the RAM chip and the number of parameters was increased.  

The abbreviation for Double Data Rate is DDR. It is used in laptops, computers, and double data chunks are transferred to memory per clock cycle.

Since the launch of DDR RAM, there have been many upgrades in the market, such as DDR2, DDR3, and DDR4. But all versions of DDR RAM failed to be compatible with the later or earlier RAM.  

Comparison Table

Parameters of Comparison	DDR2	DDR1
Channel bandwidth	3.20-8.50 GBps	1.60-3.20 GBps
Bus clock speed	200 MHz-533 MHz	100 MHz-200 MHz
Internal banks	4 or 8	4
Internal rate	100-266 MHz	100-200 MHz
Data strobes	Single-ended or differential	Single-ended

What is DDR2? 

DDR2 SDRAM represents Double Data Rate 2 in which SDRAM is Synchronous Dynamic Random-Access Memory. In 2003, it replaced DDR SDRAM, and in 2007, replaced by DDR3 SDRAM.

DDR2 DIMMs are not compatible with DDR and DDR3. The speed of DDR2 is 1066 MT/s, 800 MHz, 667 MHz, 533 MHz, and 400 MHz.

DDR2 allows for higher bus speed, and the internal clock runs at half of the speed of the data bus and requires low power.

The two factors are produced by combining four data transfers per internal clock cycle. In terms of supply voltage, DDR2 has a standard supply voltage of its 1.8V.

The internal clock of DDR2 runs at half the external clock rate of DDR1.

The memory modules of DDR2 with the top rating are at least twice as fast as the memory modules of DDR1, which are best rated. DDR2’s transfer speed varies between 0.40- 1.06 GT/s (Giga transfers per second).

The commercially available DDR2 DIMMs have a maximum capacity of 8GB. However, support and chipset availability for those DMMs is sparse, and the more common 2GB per DIMM are used.

Regarding reading latency, DDR2 has a read latency of 3-9 clock cycles, dependent upon the setting. The internal rate for DDR2 is 100- 266 MHz.

What is DDR1? 

DDR SDRAM represents Double Data Rate in which SDRAM is Synchronous Dynamic Random-Access Memory. It is used in computers due to its class of integrated circuits memory.

DDR SDRAM is also widely known as DDR1 SDRAM. DDR1 was released in 1998 by Samsung and JEDEC. When it comes to supply voltage, DDR1 standard supply voltage of 2.5V

DDR SDRAM has many generations, like DDR5 SDRAM, DDR4 SDRAM, DDR3 SDRAM, and DDR2 SDRAm. But its successors from backwards or forward are inefficient to be compatible with DDR1.

This means that memory modules of DDR2, DDR3, DDR4, and DDR5 failed to work in DDR1-equipped motherboards.

In comparison to SDR SDRAM or Single Data Rate SDRAM, with strict control of the timing of the clock signals and electrical data, the interface of DDR SDRAM can make higher transfer rates.

We use schemes such as self-calibration and phase-locked loops to reach the needed timing accuracy implementations. The modules of DDR1 are 200-pin SODIMM, 184-pin DIMM unbuffered, and 172-pin Micro DIMM.

The interface uses double pumping to double the bandwidth of the data bus but lacks a corresponding increase in the clock’s frequency.

With the down frequency of the clock, the advantage is that on the circuit board, the signal integrity requirements reduce, which mainly connects the memory to the controller.

Main Differences Between DDR2 and DDR1 

1. In terms of supply voltage, DDR2 has a standard supply voltage of its 1.8V. On the flip side, the DDR1 standard supply voltage of 2.5V.  
2. The DDR2’s transfer speed varies between 0.40-1.06 GT/s (Giga transfers per second), whereas the DDR1’s transfer for speed varies between 0.20-0.40 GT/s (Giga transfers per second).  
3. The speed of DDR2 is 400 MHz, 533 MHz, 667 MHz, 800 MHz, and 1066 MT/s. On the other hand, DDR1 is 200 MHz, 266 MHz, 333 MHz, and 400 MHz. 
4. The modules of DDR2 are 200-pin SODIMM, 240-pin DIMM unbuffered registered, and 214-pin Micro DIMM, whereas the modules of DDR1 are 200-pin SODIMM, 184-pin DIMM unbuffered, and 172-pin Micro DIMM.  
5. Regarding reading latency, DDR2 has a read latency of 3-9 clock cycles dependent upon setting, whereas DDR1 has 2, 2.5, and 3 clock cycles as its read latency. 

References

1. https://cancerdiscovery.aacrjournals.org/content/1/1/78.short
2. https://www.nature.com/articles/s41587-019-0224-x?_hsenc=p2ANqtz–g6Ln9XUyz2YtPsZXx0Op_Q-R6xpXqa4MCA9bwCgvqE5oL4CJ33z–iCqIjznQG9ewqDwQVZEUbAIdITH6IHYMKf2wWw&_hsmi=76370869

Last Updated : 11 June, 2023