This guide outlines the main differences between solid state drives (SSDs) and hard disk drives (HDDs).

There are two major types of SSD in current production — NAND and DRAM. This guide focuses on the more common one: NAND.

It’s worth noting that advances are being made all the time on both types of drive and that these differences are generalisations. Individual performance will vary from manufacturer to manufacturer.

1. Speed

Most solid state drives, except ones made using cheaper components, are significantly faster at reading data than a hard drive.

This is because there are no moving mechanical parts on a SSD and so the “seek time” is significantly reduced. Incidentally, DRAM drives are faster still.

Writing large files is also generally quicker on a SSD, though at present there are often performance problems when trying to write a lot of small files to a SSD. It’s possible to overcome this through improved system design.

In general, though, SSDs are faster than HDDs.

(PS: SSDs are generally quieter than HDDs because they don’t have any moving parts and are usually fanless)