Differences Between SSD and HDD

What is the difference between SSD (Solid State Drives) and HDD (Hard Disk Drives)? There’s no straight-forward answer to this question; buyer can evaluate the decision based on your different needs, preferences, and of course budget. There are different advantages and disadvantages to each type of drive if performance and fast bootup is your primary consideration and money is secondary, then SSD is the way to go.


SSD stands for Solid State Drive, are a newer technology, but have progressed rapidly, increasing more storage capacity each year. Solid State Drives rely on electronic storage in non-volatile memory, meaning that data won’t disappear when the computer is turned off. Solid State drive can be thought of like an oversized and more faster version of the humble USB memory stick. There are no moving parts to an SSD, Information is stored in microchips like a memory stick. An HDD uses a mechanical arm with a read/write head to read information from the storage platter. This difference is what makes SSD much faster than SDD.

Solid State Drive uses NAND technology(a kind of flash memory), it’s a non-volatile type of memory. Non-volatile means data won’t be lost if you turn off the disk. The data in Solid State Drives can remain forever. There is an SSD controller that retrieve or update data and keeps track of all the data. Look at the images below, the microchips encased inside a plastic or a metal case and look like a battery.


NavigateStorage-Samsung-SSD-850-ProSSD Top Side


NavigateStorage-Samsung-SSD-850-Pro-BottomSSD Bottom Side



Hard Disk Drives was introduced in 1956 by IBM. It is nearly 60-year old technology, steadily adding their storage capacity and compacting their physical size. HDD uses a mechanical arm with a read/write head above the spinning platters for reading and writing data. The performance of an HDD depends upon the spinning speed of the platter. The major advantage of HDD over SDD is that it is capable of storing huge amount of data cheaply. Spinning speed of platters in today’s laptop is at either 5400 RPM or 7200RPM.

HDD & SDD look similar from outside, hard disk drives use SATA interface. Commonly the form factor for laptop hard drives is 2.5 while a larger 3.5 form factor is used in desktop computers. The storage capacity of HDD is directly
proportional to the size of the platters.  Below image shows how a hard disk drive looks like.


Hitachi-Deskstar-7K4000HDD Top Side


Hitachi-Deskstar-7K4000-BottomHDD Bottom Side

Comparison between SSD and HDD

Attribute SSD (Solid State Drive) HDD (Hard Disk Drive)
Power Draw / Battery Life It uses about 2-3 watts, which gives 30+ minute battery boost It uses more battery an average of 6-7 watt
Cost More expensive than Hard Disk Drive It is cheaper than SDD
Capacity 1 TB for notebook size drives, maximum of 4 TB for desktops High capacity with between 500 GB to 1 TB for notebook size drives, maximum 10 TB for desktops
Operating System Boot Time SSD average boot time is 10-13 seconds HDD average boot time is 30-40 seconds
Noise No sound is produced as there are no moving parts Sounds of clicks and spinning are audible
Vibration Does not cause vibration Sometimes vibrate due to spinning platters
Heat Produced Less heat is produced as there are no moving parts More heat is produced due to moving parts
Failure Rate It has a mean time between failure rate of 2.0 million hours It has a mean time between failure rate of 1.5 million hours
File Copy / Write Speed Faster than HDD(200-550 MB/s) Speed of copying is 50-120MB/s
Encryption FDE (Full Disk Encryption) is supported FDE is supported
File Opening Speed Files open 30% faster than HDD Slower than HDD
Magnetism Affected? Magnetism does not cause any data loss Data can be erased due to magnetism


Hard Disk Drives are cheaper and you can get more storage space. Whereas Solid State Drives are faster, lighter, and uses less energy.

Cost Speed Durability Highest capacity Energy efficiency
HDD Cheaper Slower Less durable 10TB Use more energy
SSD More expensive Faster More durable 4TB Use less energy