HDD vs SSD: Comparison of Hard Disk Drive and Solid State Drive

Hey friends, we are going to compare  the two types of storage drives which are  commonly used to store the data permanently  in desktop and the laptops.

Now, conventionally these hard disk drives  are used as a storage solution in desktop  and the laptop.

And these hard disk drives are in use for  more than two decades.

But in recent years, the SSDs or solid state  drives are gaining the popularity because  of its speed and the performance.

So, in this video, let's compare these two  drives in aspects like speed and performance,  working principle, cost and the storage capacity  and many other aspects.

So, first of all, let's compare these two  drives in terms of their speed and the performance.

Now, the technology of hard disk drive has  improved significantly over the past two decades.

And the data density of this drive has increased  tremendously.

But the speed of hard disk drive hasn't increased  at the same pace.

Typically, the access time of today's hard  drive is in the range of few ms.

And the sequential read or write speed is  typically around 100 MBPS.

If you are thinking the speed of the hard  drive is not bad then let me tell you that  the access time of RAM and the cache memory  which is used in the computer is in the range  of nanoseconds.

Which is significantly less than the access  time of these hard drives.

So, even if you have very high-end CPU, coupled  with graphics card and RAM, still you will  not be able to extract the best performance  out of that system if you are stuck with the  slow hard disk drives.

Now, here don't get me wrong.

The with top CPU and GPUs, the performance  of the system will definitely increase.

But because of the limitation of the hard  drive, the system boot time and the opening  of the applications will not be that fast.

While on the other end, if we talk about the  SSDs, they are much faster and have access  time typically in the range of microseconds.

And typical sequential read and write speed  is in the range of 400 to 500 MBPS.

And in fact, even it is possible to achieve  the sequential read and write speed in the  range of Giga Bytes per second using this  SSDs.

So, now let's look into the internal structure  of these drives and let's find out why SSDs  are so fast and hard disk drives are relatively  slow in comparison to these SSDs.

So, if you look inside the hard disk drive,  it consists of rotating disk, which is commonly  known as the platers.

So, these platters rotate at the typical speed  of 5400 or 7200 RPM in laptops.

And it can go up to 10000 RPM in desktop computers.

And in some enterprise hard disk, the speed  can go up to 15000 RPM.

So, in these hard disk drive, the data is  stored magnetically on these platters using  the head.

And typically the data is stored in this hard  disk drive in form of tracks and the sectors.

Now, as it involves the mechanically moving  parts, there is a limitation on the speed  at which the data can be accessed or written  on these hard disk drives.

On the other end, the SSDs are designed using  the flash memory.

And to be precise if I say, they are designed  using the NAND flash memory.

So, as these SSDs are designed using the NAND  flash memory, and does not have any moving  part, they have very fast access time and  very low latencies.

So, apart from the flash memory, the SSD also  contains the microcontroller and the small  cache memory.

So, using the microcontroller, the flash memory  cells can be accessed or programmed.

And using the cache memory it is possible  to store the incoming and the outgoing data  temporarily.

Ok, so now let's compare the two drives in  terms of the form factor.

So, today's hard disk drives are typically  available in two form factors.

For desktop, it is available in 3.5-inch form  factor, while for a laptop it is available  in 2.5-inch form factor.

On the other end, the SSDs are available in  many form factors.

The most common is the 2.5-inch form factor,  where these drives can be used or replaced  in place of hard disk drives.

Apart from these, the mSATA and the M.2 SSDs  are available in very small form factors.

And they are used in ultrabooks and tablets.

Alright, so now let's compare these two drives  in terms of the system interface.

So, the system interface defines how these  drives are connected or interfaced with the  system.

So, the earlier hard drives were connected  to the system using the PATA interface.

Which is known as the parallel ATA.

But today's hard drives are connected to the  system using the SATA interface.

While enterprise hard drives are connected  to the system using the SAS protocol.

On the other end, if we talk about the Solid  State Drives, mSATA and SATA hard drives are  connected to the system using SATA interface.

While M.2 SSD can communicate with the system  using either SATA or PCI express bus.

So, now if we compare these drives in terms  of the storage capacity then for the hard  disk drive, 1TB capacity is most common in  desktops and laptops.

But for desktops, even 10 Tery Bytes of hard  drives are commonly available in markets.

And if we talk about the SSDs, then as of  now the SSDs are available from 120GB up to  4TB.

For laptops typically, it is available from  120 GB up to 1TB.

While for the desktop it is available up to  4TB.

But if we talk about the cost, then these  SSDs are much costlier than the hard disk  drives.

As of now the cost per GigaBytes for SSD is  almost 3 to 4 times the hard disk drive cost.

But as the demand of SSD is growing, the cost  is also reducing.

And perhaps one day, it will become as cheap  as the today's hard disk drives.

So, now let's compare these drives in terms  of the power consumption and the reliability.

So, as these hard disk drives inc=volves the  mechanical moving part the power consumption  of this drive is more than the SSDs.

And they are more prone to the damages in  case of shock and the vibrations.

So, now finally let's compare them in terms  of the data durability.

So, in terms of the data durability, hard  drives are more durable and data can be stored  for longer times without being powered up.

Apart from that as we have seen, these SSDs  are designed using the flash memory.

And because of that the number of programs  or erase cycles that can be performed on these  SSDs are limited.

Typically, it used to be in the range of 10000  to 100000.

And depends upon the quality of the controller  as well as the internal structure of the flash  memory.

Now, some manufacturers also provide the endurance  rating for these SSDs.

And typically it is defined by the term drive  writes per day.

It means that the number of times the user  capacity of the drive can be written per day  over the warranty period.

For example, if you have 100GB of a drive,  which has DWPD rating of 10, it means that  1000GB or 1TB of data can be written into  this drive every day over the warranty period.

So, basically, this term defines the endurance  rating for the SSDs.

But for most of the users, this rating is  quite significant.

And even if someone uses this SSD quite extensively  then also it will work reliably over more  than 5 years.

So, overall SSDs have many advantages over  the hard disk drives.

But as of now, these SSDs are quite costlier  than the hard disk drives.

So, if someone is looking for big storage  pull, with the reasonable cost then he can  go for the hard disk drive.

While on the other end, if someone wants very  fast performance and willing to pay extra  money for that performance then one can go  for the SSDs.

So, that's it for this video.

I hope in this video you understood the basic  differences between the SSD and hard disk  drive.

So, if you have any question or suggestion  do let me know in the comment section below.

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