DDR2 and DDR3 are the versions of DDR RAM memory in which DDR3 is a more advanced version and is enabled with more capabilities like high data transfer speed, low power consumption, memory reset options, more memory, etcetera. But the main difference lies within the data rate where DDR3 provides twice of the speed provided by DDR2.
With the advancement in technology, the faster versions of memories were also developed such as DDR (Double Data Rate) memories. The main concept behind the DDR memories is that by applying row address to the chip a large number of bits are accessed at the same time inside the chip.
There are several techniques used for increasing the speed of the bit transfer from pins to the chip. To effectively utilize the clock speed the data is externally transported to the rising and falling edges of the clock, this is the reason these memories are known as Double Data Rate memory.
Content: DDR2 Vs DDR3
Comparison Chart
| Basis for comparison | DDR2 | DDR3 |
|---|---|---|
| Clock frequency (theoretical) | 400 - 800 Mhz | 800 - 1600 Mhz |
| Transfer data rate | 400 - 800 Mbps | 800 - 1600 Mbps |
| Supply voltage | 1.8 volts | 1.5 volts |
| Prefetch bit width | 4 bit | 8 bit |
| Memory reset option | No provision of reset options | Provided |
| Power consumption | High | Low |
| Speed | Slower comparatively | Faster |
| Latency | 2 - 5 | 7 - 11 |
| Performance | Better than DDR3 | Average |
| Cost | Less | More |
Definition of DDR2
The DDR2 is the second version of the DDR (Double Data Rate) memories. These versions of the RAM was developed to achieve a high data rate for the block-transferring. It can transfer data at the clock rate of 400 to 1066 Mhz.
The DDR 2 version is the successor of the DDR where the main change is applied to the operational frequency of the RAM chip and prefetch buffer and the quantity of both of the parameters have been increased. A prefetch buffer is a 4 bit of memory cache, resides in the RAM chip of DDR2. The buffer is used in RAM chip for prepositioning the bit in the data bus as fast as possible.
DDR2 is a 240 pin DIMM (Dual In-line Memory Module) architecture that operates at 1.8 volts. These DIMMs are composed of the one or more than one RAM chips in a single board connected to the motherboard. The voltage of the DDR2 is reduced from its antecedent DDR technology to eliminate the heat effect.
DDR employs 144 pin DIMM design and functions at the voltage of 2.4 volts. There is no compatibility between the DDR2 and DDR, as both use different motherboard socket and DIMM key.
Definition of DDR3
DDR3 is the advanced version of the DDR2 which has increased the prefetch buffer to 8 bit and the operating frequency up to 1600 Mhz. However, the amount of power has reduced to 1.5 volts which also decreases the heating effect of the high frequency. The pin architecture of DDR3 also has 240 pins, but these can not be used in the motherboard RAM of DDR2 because of the different notched key.
In DDR3 there is a unique option available for clearing the memory by a software reset action, i.e., memory reset. The memory reset option ensures that the memory is cleared and empty after rebooting the system.
Key Differences Between DDR2 and DDR3
- The DDR2 memories work on the range of 400 to 800 Mhz and generate the data rates up to 800 Mbps. On the contrary, the DDR3 operates on the range of 800 to 1600 Mhz clock frequency and produces data transfer speed up to 1600 Mbps.
- DDR2 consumes more power as the supplied voltage for it is 1.8 volts. In contrast, for DDR3 the supplied voltage is 1.5 volt which is less than DDR2 and it also significantly reduces the heating effect which arises due to high frequency.
- The prefetch buffer in the DDR2 is of 4-bit size while DDR3 contain 8-bit buffer.
- Memory reset options are available in DDR3 but not in DDR2.
- DDR3 is comparatively faster than DDR2.
- Lower the latency better the performance, DDR2 has less value of latency and has a better performance relative to the DDR3.
- DDR3 is costlier than DDR2.
Conclusion
DDR2 is the earlier version and is an outdated technology, and DDR3 is later version of the DDR where DDR3 is improved and provides more features such as increased storage space, low power consumption, faster clock speed, system flexibility.
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