Difference between DDR2 and DDR3 Memory

In this article, we are going to discuss the difference between the DDR2 and DDR3 and different versions of DDR (Double Data Rate Version). The major question here is: What is DDR? It is a type of RAM (Random Access Memory). In computer systems, RAM is a temporary memory storage device. The computer requires RAM for the execution of every small command or process.

For instance, if a computer system wants to run a process, it first looks up the RAM for the data. If it is unable to find the RAM or the data in RAM, it then moves toward the secondary storage device, i.e., the hard disk drive, to complete the processing. This fetching of data from a hard drive is really time-consuming. It cannot be ignored in modern computer systems, as sluggish computers are not an option in this era.

Comparison Chart of DDR2 and DDR3

	DDR2 RAM	DDR3 RAM
Clock	The clock frequency of DDR2 is in the range of 400 MHz – 800 MHz.	The clock frequency of DDR3 is in the range of 800 MHz – 1600 MHz.
Rate of data transfer	The data transfer rate is in the range of 400 Mbps – 800 Mbps.	The rate of data transfer is in the range of 800 Mbps – 1600 Mbps.
Working/supply voltage	The supply voltage of DDR2 is 1.8 V.	The supply voltage of DDR3 is 1.5 V.
Abbreviation	Double Data Rate version 2.	Double Data Rate version 3.
Market value	The market value of DDR2 is cheaper.	It is quite expensive in comparison to DDR2.
Performance	It has better performance.	It is average in performance; DDR2 is better.
Power consumption	DDR2 consumes a very large amount of power.	Power consumption is lower in comparison to DDR2
Speed	Speed is slower.	Speed is faster.
Memory reset option	No memory reset option is available.	The memory reset button is available in DDR3.

RAM and its types

The addition of new RAM to the processing cycles of the computer can improve its sluggishness (slow speed). After a brief introduction to RAM, let’s now move on to the basics of DDRs. A DDR is one of many types of RAM. DDR RAM is its common name; however, it is also known as DDR2SDRAM (Double Data Rata Synchronous Dynamic Random Access Memory 2) and DDR3SDRRAM (Double Data Rata Synchronous Dynamic Random Access Memory 3).

DDR RAM and its Versions

The name, Double Data Rate RAM, is because it was able to transfer two data packets per cycle. With each different version, along with many other differences, the major difference was the change in the number of data packets per cycle. For instance, the number of data packets per cycle changes from two to four with a single version upgrade, i.e., it was two in the first version of DDR and four in DDR2. In normal SDRAM (previous version of DDR), the data transfer occurs on only the rising edge of the clock cycle, whereas in the upgraded version (DDR), the data transfer occurs on both the rising and falling edges of the clock cycle. However, with each version upgrade, both clock edges are already in use, but the data transfer packets can be increased by increasing the clock cycle frequency (double in DDR2 and triple in DDR3).

As we move from DDR to DDR5, the clock frequency of the RAM increases by one-fold for each version. Also, in order to make a successful upgrade in the versions of RAM, we must also upgrade the hardware, i.e., the motherboard, accordingly. And with the upgrade to the DDR version, the efficiency of the machine increases and the performance decreases. Let’s make it a little more precise and move towards the definition of DDR2 and DDR3 specifically.

DDR2 (Double Data Rate version 2)

In the family of DDR SDRAM, version 2 is the second in the number of generations. As we have discussed previously in DDR2, the clock frequency of RAM data transfer increases to double, supporting 4 data transfers per clock cycle in the previous version of DDR. The buffer of the RAM is a 4-bit cache memory; this buffer was used for the prepositioning of the data bit before processing in order to increase the speed, and the operating voltage of the DDR2 is 1.8 V, which is a little higher than the operating voltage of the DDR3. The reduction in the operating/supply voltage was in order to reduce the heat effects in the latest version.

In the last version of DDR, the operating voltage was higher and the number of DIMM (Dual In-Line Memory Module) pins was lower. But with every upgrade, the goal is to decrease the operating voltage and increase the number of pins. In DDR3, the number of DIMM pins is 240. Hence, one or more RAM chips are used for the composition of these DIMM’s to form a single board, and that single board is connected to the motherboard.

The clock frequency of DDR2 is in the range of 400 MHz to 800 MHz, which is double the frequency of DDR1 and half the frequency of DDR3. The speed of the transfer of data (data transfer rate) in DDR2 is 0.8 GT/s. Among all the available capacities of DDR2, the most common is 4GB; however, 2GB of DDR2 is also present. The theoretical background of DDR2 is 6.4 GB/s.

DDR3 (Double Data Rate version 3)

This is the third generation (third version) in the DDR family, and the changes in it go in the same direction as in DDR2. The prefetch buffer in DDR3 is increased as compared to the buffer in DDR2 and DDR1, i.e., it has an 8-bit buffer for the prepositioning of bits in order to increase speed.

The operating frequency of the DDR ranges from 800 MHz to 1600 MHz, which is double the frequency of the previous version. The data transfer rate of DDR3 is double that of DDR2, i.e., it is 1.6 GT/s, and the theoretical background of DDR3 is 12.8 GB/s.

With every version, the operating voltage of the DDR decreases to a specific level. The same is the case in DDR3, where the operating voltage is reduced to 1.5 V. The number of DIMM pins remains the same, but we cannot use them in the same way with the motherboard, as in the case of DDR2. The difference in version results in the pin configuration with the motherboard.

Conclusion

Both DDR2 and DDR3 are double data rates of RAM, just a variation in the version or the release. Similarly, every software or hardware device has different versions. The vendor keeps upgrading them on the demand of the consumer or customer, as is the case with DDR technology. According to the needs of the users or customers, the former version of DDR, i.e., DDR2, requires an upgrade, and the version next to 2 is 3 (as is obvious). However, the above discussion gives a brief and comprehensive comparison between their performance, market value, speed, frequency, etc.