We have received series of messages on the difference between an SSD and HDD storage device and we have decided to put up this article that clearly states the difference between this two major computer storage devices.

What is an SSD?

SSD stands for Solid State Drive, it may also be referred to as a solid-state disk.

It is a nonvolatile storage device that stores persistent data on solid-state flash memory.

You’re probably familiar with USB memory sticks - SSD can be thought of as an oversized and more sophisticated version of the humble USB memory stick, there are no moving parts involved.

What is an HDD?

HDD stands for hard disk drive. It is a data storage device that uses magnetic storage to store and retrieve digital information using one or more rigid rapidly rotating disks coated with magnetic material. 

Major Differences Between an SSD and HDD

Both SSD and HDD do the same job: They boot your computer, and store your programs and personal files. But each type of storage has its own unique feature set. How do they differ, and why you would like to get one over the other?

Speed

This is where SSD shine. An SSD-equipped PC will boot in less than a minute, and often in just seconds. A HDD requires time to speed up to operating specs, and will continue to be slower than an SSD during normal use. A Windows PC or Mac with an SSD boots faster, launches and runs apps faster, and transfers files faster. Whether you're using your computer for fun, school, or business, the extra speed may be the difference between finishing on time and failing.

Capacity

HDD is the workhorses when it comes to sheer capacity and how much data can be stored. SSD is only affordable at lower capacities. High-capacity SSDs are extremely expensive.

Price

At a system level, low-capacity SSD can be affordable in the 32GB to 64GB range. But high-capacity SSD is very expensive, especially when measured by cost per gigabyte. HDD provides the lowest cost per gigabyte.

Power

SSD does not have to expend electricity spinning up a platter from a standstill. Consequently, none of the energy consumed by the SSD is wasted as friction or noise, rendering them more efficient. On a desktop or in a server, that will lead to a lower energy bill. On a laptop or tablet, you'll be able to eke out more minutes (or hours) of battery life. In general, storage will not impact battery life in a laptop computer by more than about 10%. Processor power and LCD really run down the battery. However, SSD is more power-efficient.

Durability

SSD has no moving parts, so it is more likely to keep your data safe in the event you drop your laptop bag or your system is shaken about by an earthquake while it's operating. Most hard drives park their read/write heads when the system is off, but they are flying over the drive platter at a distance of a few nanometers when they are in operation. Besides, even parking brakes have limits. If you're rough on your equipment, an SSD is recommended.

How data is stored

SSD stores data in NAND-based flash memory, HDD stores data in a magnetic form on a thin film of ferromagnetic material on a disk.

Weight

SSD is Lighter compared to HDD

Components

Reliability and lifetime

SSD has no moving parts to fail mechanically. Each block of a flash-based SSD can only be erased (and therefore written) a limited number of times before it fails. HDD has moving parts, and are subject to potential mechanical failures from the resulting wear and tear.

Noise

Even the quietest HDD will emit a bit of noise when it is in use from the drive spinning or the read arm moving back and forth, particularly if it is in a system that it's been banged about or if it's been improperly installed in an all-metal system. Faster hard drives will make more noise than those that are slower. 

SSD has no moving parts and make virtually no noise, although electric noise from the circuits may occur.

Temperature control

SSD does not require any temperature cooling and can tolerate high temperatured. HDD requires good temperature cooling system because high temperatures can shorten the life of the HD.

Secure writing limitations

SSD flash memory cannot be overwritten, but has to be rewritten to previously erased blocks. If a software encryption program encrypts data already on the SSD, the overwritten data is still unsecured, unencrypted, and accessible (drive-based hardware encryption does not have this problem). Also data cannot be securely erased by overwriting the original file without special "Secure Erase" procedures built into the drive.

HDD can overwrite data directly on the drive in any particular sector. However the drive's firmware may exchange damaged blocks with spare areas, so bits and pieces may still be present. 

Availability

Hard drives are more plentiful in budget and older systems, but SSDs are becoming more prevalent in recently released laptops. That said, the product lists from Western Digital, Toshiba, Seagate, Samsung, and Hitachi are still skewed in favor of hard drive models over SSDs. For PCs and Mac desktops, internal hard drives won't be going away completely, at least for the next few years. SSD model lines are growing in number: Witness the number of thin laptops with 256 to 512GB SSDs installed in place of hard drives.

Form Factors

Because HDD rely on spinning platters, there is a limit to how small they can be manufactured. There was an initiative to make smaller 1.8-inch spinning hard drives, but that's stalled at about 320GB, since the phablet and smartphone manufacturers have settled on flash memory for their primary storage. SSD has no such limitation, so they can continue to shrink as time goes on. SSD is available in 2.5-inch laptop drive-sized boxes, but that's only for convenience. As laptops continue to become slimmer and tablets take over as primary platforms for Web surfing, you'll start to see the adoption of SSD skyrocket.

Summary

HDDs win on price, capacity, and availability. SSDs work best if speed, ruggedness, form factor, noise, or fragmentation (technically part of speed) are important factors to you. If it weren't for the price and capacity issues, SSD would be the hands-down winner.

The Storage of Tomorrow

It's unclear whether SSD will totally replace HDD, especially with shared cloud storage waiting in the wings. The price of SSD is coming down, but they are still too expensive to totally replace the terabytes of data that some users have in their laptop computers. Cloud storage is not free, either: You will continue to pay as long as you want personal storage on the Internet. Local storage will not go away until we have ubiquitous wireless Internet everywhere, including in planes and out in the wilderness. Of course, by that time, there may be something better.