Monday, 4 November 2019

What is Difference Between HDD vs SSD? | Which Should I Buy?

In this article, we are going to compare two types of storage drives which are HDD and SSD.  They are commonly used to permanently store data on desktops and laptops.

What is difference between HDD vs SSD

 Now, traditionally these hard disk drives are used as storage solutions in desktops and laptops.  And these hard disk drives (HDD) have been in use for more than two decades.
 But in recent years, SSDs i.e. "solid states drives" are gaining popularity Because of its speed and performance.

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

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

  •  Now, the technology of hard disk drive (HDD) has improved a lot in the last two decades.
  •  And the data density of this drive is greatly enhanced.
  •  But the hard disk drive (HDD) speed has not increased at the same speed.
  •  Typically, today's hard drive access times are in the range of a few ms.
  •  And sequential read or write speeds are typically around 100 Mbps.
  •  If you are thinking that the hard drive (HDD) speed is not bad then let me tell you RAM and cache memory used in the computer is within the time limit of access
  •  Of nanoseconds.  
  • Which is much less than the access time of these hard drives (HDD).

 So, if you have a very high-end CPU, coupled with a graphics card and RAM, you will still
 You are not able to extract the best performance from that system if you are stuck with
 Slow Hard Disk Drive (HDD).

 With top CPUs and GPUs, system performance will definitely increase.
 But due to hard drive (HDD) limitation, system boot time and opening
 Applications will not be this fast.

 Whereas on the other end, if we talk about SSDs, 

  • they are very fast and their reach is usually time in the range of microseconds.
  •  And typical sequential read and write speeds are in the range of 400 to 500 Mbps.
  •  And indeed, it is possible to achieve even sequential read and write speeds
  •  Using these SSDs, the limit is increased to Gigabytes per second.

 So, now let's look at the internal structure of these drives

  Let us know why SSD So fast and hard disk drives (HDD) are relatively slow compared to these SSDs.

  •  So, if you look inside the hard disk drive (HDD), it has a rotating disk, Most commonly known as platters.
  •  Therefore, these plots rotate in laptops at a specific speed of 5400 or 7200 RPM.
  •  And it can go up to 10000 RPM in desktop computers.
  •  And in some enterprise hard disks, speeds can go up to 15000 RPM.
  •  So, in these hard disk drives, the data is magnetically stored on the heads of these platters using.
  •  And typically data is stored in hard disk drives as tracks and sectors.
  •  Now, since it consists of mechanically moving parts, there is a limit on speed
  •  On which data can be accessed or written to these hard disk drives.

  •  On the other end, SSDs are built using flash memory.
  •  And to be precise if I say, they are designed using NAND flash memory.
  •  So, as these SSDs are designed using NAND flash memory, and have no moving parts.
  •  They have very fast access time and very low latency.
  •  So, in addition to flash memory, SSD also has microcontroller and small
  •  cache memory.
  •  Therefore, using a microcontroller, flash memory cells can be accessed or programmed.
  •  And it is temporarily possible to store incoming and outgoing data using cache memory .

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

  •  So, today's hard disk drives (HDD) are generally available in two form factors.
  •  For desktops, it is available in the 3.5-inch form factor, while for laptops it is available
  •  In 2.5-inch form factor.

  •  On the other end, SSDs are available in several 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 drive.

 Apart from these, mSATA and M.2 SSDs are available in very small form factor.
 And they are used in ultrabooks and tablets.

 Okay, so now compare these two drives in terms of system interface.

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

 Therefore, the first (HDD) hard drives were connected to the system using the PATA interface.
 Which is known as parallel SATA?

 But today's hard drives are connected to the system using the SATA interface.
 While the enterprise hard drive is connected to the system using the SAS protocol.

 On the other end, if we talk about solid-state drives (SSD) then mSATA and SATA hard drives are
 Connected to the system using the SATA interface.
 Whereas M.2 SSD can communicate with the system using SATA or PCI Express bus.

 So, now if we compare these drives in terms of storage capacity

  So hard Drive for (HDD)
 Hard disk drives, 1TB capacity are most common in desktops and laptops.
 But for desktops, even 10 terry bytes of the the the same time as these time the hard drive is usually available in markets.

 And if we talk about SSDs, till now SSDs are available up to 120GB
  4 TB.
 Typically for laptops, it is available from 120 GB to 1 TB.
 While for desktop it is available up to 4TB.
 But if we talk about the cost, then these are very expensive drives compared to SSD hard disk.
 So far the cost per GigaBytes for SSD is about 3 to 4 times the cost of the hard disk drive.

 But as the demand for SSD is increasing, the cost is also coming down.
 And maybe one day, it will become as cheap as today's hard disk drives (HDD).

 So, now compare these drives in terms of power consumption and reliability.

 Therefore, as these hard disk drives = mechanical moving part controls the power consumption
 This (HDD) hard disk drive is more than SSDs.
 And they are more prone to damage in terms of shock and vibration.

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

 So, in terms of data durability, hard drives are more durable and data can be stored.
 Long-time without operating.
 Also as we have seen, these SSDs are designed using flash memory.
 And because of that, the number of programs or deleted cycles that can be done on them
 SSDs are limited.
 Usually, it used to be in the range of 10000 to 100000.
 And depending on the quality of the controller as well as the internal structure of the flash
 Now, some manufacturers also provide endurance ratings for these SSDs.
 And it is usually defined by the term drive written per day.
 This means that the user capacity of a hard disk drive (HDD) can be written multiple times per day
 In the warranty period.

 For example, if you have 100GB of hard disk drive (HDD), with a DWPD rating of 10, this means
 1000GB or 1TB of data can be written to this drive every day during the warranty period.
 So, basically, the term defines endurance ratings for SSDs.
 But for most users, this rating is quite important.
 And even if someone uses this SSD extensively, it will also work reliably
 Up to 5 years.

 So, SSD has many advantages over a hard disk drive (HDD) overall.
 But so far, these SSDs are significantly more expensive than hard disk drives (HDD).
 So, if someone is looking for a large storage bridge at a reasonable cost, he can
 Go for hard disk drive (HDD).

 Whereas on the other end, if someone wants very fast performance and is willing to pay extra
 For that performance, anyone can go for SSD.


 I hope that in this article you have understood the basic difference between SSD and hard disk drive (HDD).
 So, if you have any questions or suggestions, let me know in the comment section below.