In the vast majority of cases, computers load their
programs and data from an internal HDD (Hard Disk
Drive).
Hard Disk Drives are basically boxes of rotating
disks which use a stylus to read data from the disks.
They are fitted internally to PCs and laptops and
need to accelerate to operating speed for data to be
read.
A 5400rpm hard disk will need to
accelerate to 5400rpm, the stylus will need to move
to the disks, find the required files and retrieve
them.
The above process obviously causes wear,
generates heat, generates noise and uses power.
Because SSD is a Solid State Drive, it uses less
power, it is virtually silent, generates virtually
no heat and there is no wear (there are no moving
parts).
SSD units (Solid State Drives) are basically boxes of memory. This
is why
a quality SSD is far more reliable, silent,
generates minimal heat, uses minimal power and is
always significantly faster than a hard drive
(the drive does not need to accelerate to operating
speed and the stylus does not need to search the
drive for data).
Overall, an SSD drive is usually the best single
upgrade that can currently be made to most computers (tower
PCs, desktop PCs and laptops), followed closely by
memory upgrades.
Although the capacity of SSDs tends to be lower than
Hard Disk Drives, in most cases this is not an
issue.