SSD (Solid State Drive) is a data storage device that uses non-volatile memory to store data. The SSD using SRAM or DRAM (instead of flash memory) is often called a RAM-drive. With no moving parts, solid-state drives are less fragile than hard disks and are also silent; as there are no mechanical delays, they usually enjoy low access time and latency.
Some advantages and disadvantages of SSDs over Hard Drives are as follow:
Advantages of SSDs:
- Faster start-up because no spin-up is required.
- Fast random access because SSDs have no heads and thus no delays due to head motion (seeking).
- Low read latency times for RAM drives. This results in faster boot and application launch times.
- Many SSDs currently have high data transfer rate with maximum sequential read oup to 550 MB/s.
- Silent operation due to the lack of moving parts.
- High mechanical reliability, as the lack of moving parts almost eliminates the risk of "mechanical" failure.
- Ability to endure extreme shock, high altitude, vibration and extremes of temperature.
- Defragmenting the SSD is unnecessary. Since SSDs are random access by nature and can perform parallel reads on multiple sections of the drive (as opposed to a HDD, which requires seek time for each fragment, assuming a single head assembly).
Disadvantages of SSDs:
- SSD drives have limited lifetimes and will often wear out after 1,000,000 to 2,000,000 write cycles (1,000 to 10,000 per cell) for MLC, and up to 5,000,000 write cycles (100,000 per cell) for SLC.
- As of early-2014, SSDs are still more expensive per gigabyte than hard drives. Whereas a normal SSD drive costs US $0.50 per gigabyte, hard drives are around US $0.07 per gigabyte for 3.5", or US $0.15 for 2.5".
- The capacity of SSDs is currently lower than hard drives. However, SSD capacity is predicted to increase rapidly, with drives of 1TB already released for enterprise and industrial applications.