SSD = Solid State Disk
Yes, they are the platter-less hard drives. Here is a brief pro/con from wikipedia. I'll post up some numbers when I find a decent comparison, or decide to make one.
http://en.wikipedia.org/wiki/Solid-state_drive
Quote:
- Advantages
- Faster start-up because no spin-up is required.
- Fast random access because there is no read/write head[23]
- Low read latency times for RAM drives.[24] In applications where hard disk seeks are the limiting factor, this results in faster boot and application launch times (see Amdahl's law).[25]
- Consistent read performance because physical location of data is irrelevant for SSDs.[26]
- File fragmentation has negligible effect.
- Silent operation due to the lack of moving parts.
- Low capacity flash SSDs have a low power consumption and generate little heat when in use.
- 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.[27][28] This makes SSDs useful for laptops, mobile computers, and devices that operate in extreme conditions (flash).[25]
- For low-capacity SSDs, lower weight and size: although size and weight per unit storage are still better for traditional hard drives, and microdrives allow up to 20 GB storage in a CompactFlash form-factor. As of 2008 SSDs up to 256 GB are lighter than hard drives of the same capacity.[27]
- Failures occur less frequently whilst writing/erasing data, which means there is a lower chance of irrecoverable data damage.[29]
- [edit]
Disadvantages
- As of mid-2008, SSDs are still more expensive per gigabyte than hard drives. Whereas a normal flash drive is between US$1.50-3.45 per gigabyte, hard drives are around US$0.38 per gigabyte.[18][30]
- The capacity of SSDs is currently lower than that of hard drives. However, flash SSD capacity is predicted to increase rapidly, with drives of 1 TB already released for enterprise and industrial applications.[31][32][33][34][35]
- Asymmetric read vs. write performance can cause problems with certain functions where the read and write operations are expected to be completed in a similar timeframe. SSDs currently have a much slower write performance compared to their read performance.[36]
- Similarly, SSD write performance is significantly impacted by the availability of free, programmable blocks. Previously written data blocks that are no longer in use can be reclaimed by TRIM; however, even with TRIM, fewer free, programmable blocks translates into reduced performance.[37]
- Due to the low storage density of SSDs, hard disks can store more data per unit volume than DRAM or flash SSDs, except for very low capacity/small devices.
- Flash-memory cells have limited lifetimes and will often wear out after 1,000 to 10,000 write cycles for MLC, and up to 100,000 write cycles for SLC.[38][39][40][41] Special file systems or firmware designs can mitigate this problem by spreading writes over the entire device, called wear leveling.[42]
- As a result of wear leveling and write combining, the performance of SSDs degrades with use.[43][44]
- SATA-based SSDs generally exhibit much slower write speeds. As erase blocks on flash-based SSDs generally are quite large (e.g. 0.5 - 1 megabyte),[18] they are far slower than conventional disks during small writes (write amplification effect) and can suffer from write fragmentation.[45] Modern PCIe SSDs however have much faster write speeds than previously available.
- DRAM-based SSDs (but not flash-based SSDs) require more power than hard disks, when operating; they still use power when the computer is turned off, while hard disks do not.[46]
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