Pros and cons of Solid State Drives

March 3, 2009

in computer hardware,computer performance

by David Hakala

Q: What are the pro’s and con’s of switching to a Solid State Hard drive? Is it faster and is it reliable? – Bill.

A Solid State Drive (SSD) is a data storage device that uses solid-state memory to store data. “Solid-state” means that the device stores data as patterns in the on/off states of transistors. A transistor in its “on” or positively charged state is considered a binary “1” bit, while a transistor in its “off” state is considered a “zero” bit. “Solid” refers to the fact that there are no empty spaces in a transistor for mechanical parts to move around in; the transistor is turned on and off by the application of electricity, not by the electromechanical movement of a physical switch.

SSDs are designed to emulate traditional electromechanical hard drives. That is, they look just like “normal” hard drives to a computer’s operating system, and can be plugged in and used without any special preparations.

Performance-wise, an SSD beats the pants off of any traditional hard drive. An SSD is much faster, quieter, and less likely to break than an electromechanical drive. Specifically, advantages of SSDs include:

Faster start-up, as no spin-up is required; you don’t have to wait for a disk to get up to rotational speed.

Extremely fast read times because there is no mechanical read/write head to be moved from one are of a disk to another. We’re talking orders of magnitude faster than traditional drives. An SSD boots an operating system almost instantly, and loads large programs such as Microsoft Word or a Web browser in the blink of an eye.

No noise: with no moving parts, an SSD does not vibrate to make that subliminal whining noise of a rotating disk, nor do you hear the clickety-clack of a read/write head moving rapidly back and forth. Fans may be used to cool large SSDs, but their whisper is much quieter than normal hard drive operations.

SSDs are ideal for mobile computers. No moving parts also means high mechanical reliability; extreme resistance to shock and vibration, changes in altitude, and temperature extremes.

File fragmentation no longer matters. Because the physical location of data blocks makes no difference in the speed with which a complete file is read from an SSD, it becomes unnecessary to run defragmentation utilities.

Fails in the best way possible. If an SSD drive fails, it is most likely to fail during a write operation. Traditional drives typically fail during read operations. Failure to write is usually not fatal; the data is simply written to another part of the drive. Read failures typically result in lost stored data.

The biggest downside of SSDs is their current cost, which can run 10 times the dollars-per-gigabyte cost of traditional drives.

Limited write (erase) cycles is another concern with SSDs. The most expensive, “high endurance” SSD devices wear out after 1 million to 5 million write/erase cycles. Over a computer’s lifetime, frequently accessed files such as Master File Tables and activity logs can be written/erased more than that.

Slower write speeds, especially on small files.

DRAM-based SSDs consume more power than traditional hard drives and consume power even when the computer is turned off.

David Hakala has perpetrated technology tutorials since 1988 in addition to committing tech journalism, documentation, Web sites, marketing collateral, and profitable prose in general. His complete rap sheet can be seen at