HDD Vs SSD Which is the best?

HDD Vs SSD Which is the best?

We will examine HDD Vs SSD. The two types of storage devices commonly used to store the desktop and the laptops’ data permanently.

Now conventionally, these Hard Disk Drives (HDD) are used as a storage solution in desktops and laptops. These hard disk drives are in use for more than two decades.

But in recent years, Solid-State Drives (SDD) are gaining popularity because of their speed and performance. Let us compare these two drives in different aspects. Such as speed and performance, working principle, cost, storage capacity, and many other elements.

Comparison of HDD Vs SSD in terms of Speed and Performance

Now the HDD technology has improved significantly over the past two decades, and the data density of HDD is increased tremendously.

But the speed of HDD hasn’t increased at the same pace. Typically, the access time of today’s Hard Disk Drives is in the range of 2 milliseconds, and the sequential read or write speed is typically around 100 MegaBytes Per Second (MBPS).

If you think the speed of HDD is not bad, let me tell you that RAM and Cache Memory’s access timer is in the range of nanoseconds, which is significantly less than the existing all these hard disk drives.

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

The top CPUs and GPUs’ performance will increase, but because of the limitation of hard drives, the system boot time and the opening of the applications will not be that fast.

While on the other hand, if we talk about the SSD’s, they are much faster. They have an access time typically in the range of microseconds, and the typical sequential read and write speed is in the range of 400 to 500 MegaBytes Per Second (MBPS).

In fact, even it is possible to add to the sequential read and write speed in the range of GigaBytes Per Second (GBPS) using these Solid-State Drives. So now, let us look into the internal structure of these drives. Let us find out why Solid-State Drives are so fast, and Hard Disk Drives are relatively slow.


So if you look inside the HDDs, it consists of a rotating disc, commonly known as Platters. These Platters rotate at the speed of 5400 or 7200 RPM on laptops, and it can go up to 10000 RPM on desktop computers. And in some enterprise hard disks, the rate can go up to 15000 RPM.

So in this Hard Disk Drives the data is stored magnetically on these platters using the head. Typically, information is stored in these HDD’s in the inform of tracks and the sectors.

As it involves the mechanical moving parts, there is a limitation on the speed at which the data can be accessed or written on these HDDs.

HDD Vs SSD - Platter

Flash Memory

On the other hand, the SSD’s are designed using flash memory, or we can say designed using the NAND flash memory.

These Solid-State Drives are designed using flash memory and do not have any moving parts. They have very fast access times and very low latencies. So apart from the flash memories, the SSD’s also contains the microcontroller and the small cache memory.

So, using the micro-controller, flash memory cells can be accessed or programmed. Using this cache memory, it is possible to store the incoming and outgoing data temporarily.

HDD Vs SSD - Flash memory in SSD
Flash memory in SSD

Comparison of HDD Vs SSD in terms of Form Factor

So, today’s HDDs are typically available in 2 form factors.

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

On the other hand, SSD’s 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 M2 SSD are available in minimal form factors, and they can use it in ultrabooks and tablets.

Comparison of HDD Vs SSD in terms of System Interface

The system interface defines how do the drives are connected and are interfaced with the system.

The earlier Hard Disk Drives were connected to the system using the PATA interphase known as parallel ATA.

But the SSD’s are connected to the system using the SATA interphase, which is known as serial ATA. At the same time, the enterprise hard drives are connected to the system using the SAS protocol.

On the other hand, if we talk about the Solid-State Drives, the SATA and mSATA hard drives are connected to the SATA interphase system. While the M.2 SSD can communicate with the system either using the SATA or PCI express bus.

Comparison of HDD Vs SSD in terms of Storage Capacity and Cost

The HDD’s with 1 TB capacity is most common in desktop and laptops. But for desktop, even the 10 TB of HDD’s are commonly available in the market.

Suppose we talk about the SSD’s, then the SSD’s available from 120 GB up to 4 TB. For laptops, typically, it is available from 120 GB up to 1 TB. While for desktop, it is available up to 4 TB.

If we talk about the cost, then these SSD’s are much costlier than these HDDs. The price per GigaByte for these SSD’s is almost 3 to 4 times the HDD’s cost.

But as Solid State Drive’s demand is growing, the cost is also reducing, and perhaps one day it will become as cheap as the Hard Disk Drives.


Comparison of HDD Vs SSD in terms of Power Consumption and Reliability

These Hard Disk Drives contain mechanical moving parts. The power consumption of HDD’s is more than the SSD’s. Hard Disk Drives are more prone to damage in case of shock and vibrations.

Finally, Comparison of HDD Vs SSD in terms of Data Durability

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

Apart from that, we have seen, these Solid-State Drives designed using flash memory, and because of that, the number of programs that can perform on these Solid-State Drives is limited.

Typically, P/E cycles used to be in the range of 10000 100000, and it depends upon the quality of the controller and the internal structure of this flash memory.

Some manufacturers also provide endurance rating for these SSD’s. Typically, it is defined by the term Drive Writes Per Day (DWPD). It means writing the number of times the drive’s user capacity per day over the warranty period.

For example, if you have 100 GB of SSD, which has a DWPD rating of 10, it means that 1000 GB or 1 TB of data can be written into these drives every day over the warranty period. So basically, this term defines the endurance rating for the SSD’s.

But for most of the users, these ratings are quite significant. And even if someone uses these SSD’s quite extensively, it will work reliably over more than five years.

Overall, SSD’s have many advantages over hard disk drives, but these SSD’s are quite costly than hard disk drives.

If someone is looking for a big storage area with resealable cost and can go for hard disk drives.

While on the other hand, if someone wants a speedy performance and is willing to pay extra money for that performance, one can go for that SSD’s.

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