Types of Hard Drives | SATA HDD, SSD, NVMe, Which one do I need?

There are various types of hard drives, each with its own storage capacity, price range, form factor, and interface type. In this article, we will learn about some of the most common types of hard drives, such as HDD, SSD, and the latest M.2 NVMe drives, as well as their benefits and drawbacks, and determine which type of hard drive is best for you.

We enjoy storing personal information on our computers. Whether it’s photos, documents, games, movies, or music, once it’s in the computer, it’s there to stay. This is made possible by the computer’s storage device, which we commonly refer to as a Hard Drive.

Aside from personal files, the hard drive’s primary function is to store your computer’s operating system as well as various applications. That’s correct. Operating systems such as Windows or Mac are stored on these hard drives and are loaded into system memory during boot up (RAM).

What Is A Hard Drive?

A hard drive is an important piece of hardware in a computer. It is a storage device that permanently stores all types of files. When we say “all types of files,” we mean the necessary Operating System files, application-related files, and personal files (such as movies, photos, music etc.).

This type of permanent storage is also known as Non-Volatile Memory, which means that the data stored in it is retained even after the computer is shut down or power is turned off. This is in contrast to RAM, which stands for volatile memory or main system memory. Only when power is applied does the data in system memory remain there. When the system is shut down or the power is turned off, the data in the system memory is also erased.

Hard disk drives, or HDDs for short, are another name for hard drives. Over the years, hard drive technology has advanced significantly, from traditional magnetic hard drives with metal platters and read/write heads to solid state memory with no mechanical parts.

What Is the Purpose of a Hard Drive?

As previously said, a hard drive is the primary storage device that houses the operating system as well as the programs. When we boot up the machine, key OS files from the hard drive are loaded into RAM. Similarly, all applications are kept on hard drives, and when we open one by running its executable file, it is loaded into RAM from the hard drive. As a result, it is evident that a hard disk is a necessary component of a computer.

A hard disk not only holds the operating system and software, but it also keeps all of your personal data such as photographs, documents, music, movies, and games.

 Types of Hard Drives

Today’s hard drives come in a variety of interface technologies, storage capacities, and price points. Traditionally, mechanical hard drives are connected to computers via a special parallel port known as PATA, which stands for Parallel Advanced Technology Attachment.

If you built computers in the 1990s and early 2000s, you almost certainly came across these connectors. These are also known as Integrated Drive Electronics or IDE hard drives.

The bulky connector (we needed a 40-pin or sometimes an 80-pin connector) and slow data transfer rates (maximum speed could only go up to 133MB/s) prompted the development of SATA or Serial ATA technology.

Because data in SATA drives is transferred serially, the number of wires required to transfer data has been reduced to seven. This, combined with the fact that the SATA interface could support transfer rates of up to 6Gb/s, made it an obvious choice for fast boot up and loading of games and applications.

PATA and SATA drives have always been mechanical hard drives with a metal platter (or a bunch of platters) and a magnetic read / write head. The next technological advancement was not in the interface, but in the type of storage itself.

This is where Solid State Drives, or SSD, came to the fore. SSDs store data using semiconductors rather than mechanical parts. The primary component of SSDs is NAND-based Flash storage. SATA was initially the interface for SSDs.

However, the SSD’s potential is limited by the SATA interface’s 6Gb/s transfer limit. Even though SSDs can transfer data at a faster rate, we couldn’t do so if we stuck with the aging and physically limited SATA interface.

Engineers began developing a new interface for faster SSDs and created the PCI-based Non-Volatile Memory Host Controller Interface, also known as NVM Express (NVMe in short). An NVMe drive with a PCIe 3.0 interface has a transfer speed of 32GB/s (4GB/s) and a transfer speed of 64GB/s (8GB/s) with the latest PCIe 4.0 interface.

Despite all of the interfaces and storage options, hard drives can be divided into three types. They are as follows:

• Solid State Drives (SSD)
• Hard Disk Drives (HDD)
• NVMe Drives

Both HDD and SSD have SATA interfaces, while NVMe drives have PCIe interfaces. Let us now look at the three different types of hard drives and their benefits and drawbacks.

SATA Hard Disk Drives (HDD)

Hard drives with SATA interfaces are a popular option for data storage. They are significantly less expensive and frequently have a large storage capacity (few tera bytes). Because they use a SATA interface, the theoretical transfer limit of these HDDs for SATA 3.0 revision is 6Gb/s. This translates to a maximum possible transfer rate of 600MB/s (when 8b / 10b encoding is used).

It is important to note that the speeds mentioned here are theoretical SATA interface speeds that will never be achieved due to physical and mechanical limitations of HDDs.

These speeds may not be impressive today, but they are significantly faster, especially when compared to older IDE drives with a transfer limit of 133MB/s.

HDDs with storage capacities ranging from 500GB to 12 or 16GB are available. HDDs come in a variety of physical sizes, typically 3.5″ for desktop use and 2.5″ for laptops.

SATA HDDs are still a popular storage choice for low-cost bulk storage even with redundancy due to their decent transfer speeds, availability of larger storage space, and significantly lower cost (you could buy two SATA HDDs with 1-to-1 redundancy and this option would still be a lot cheaper than the SSD counterparts).

Because HDDs are mechanical devices that store data on metal platters, they are prone to wear and tear and frequently have physical damage to the platters or the read / write head. Another issue with writing data to physical disks is data fragmentation (where data is split into several smaller parts and stored in different parts of the disk).

Despite its shortcomings, people continue to purchase SATA HDDs for large data backup, storage servers, security devices, and other applications. It is still a popular storage option if you don’t require fast read/write speeds, are on a tight budget, or need a secondary storage device.

Advantages

Large capacity storage

Low Cost

Disadvantages

Data transfer speeds are limited.

Wear and tear occur in mechanical parts.

Solid State Drives (SSD)

When we talk about SSDs, we usually mean SATA-based 2.5″ Solid State Drives, though NVMe drives are technically solid state devices as well. To avoid the problem of moving mechanical parts, SSDs store data on a semiconductor device rather than a physical disk.

Before making its way into SSDs, NAND-based flash technology was used for thumb drives for quite some time. Instead of physical metal platters, data is stored on NAND-based flash memory in SSDs.

SSDs are significantly faster and can easily reach the SATA interface speeds because there is no magnetic read/write head.

The main issue with SSDs is their high cost and limited storage capacity. While SATA HDDs with capacities as large as 16TB are available, SSDs with capacities greater than 2TB are uncommon (there are few 4TB SSDs but the cost is astronomical when compared to HDDs). SSD storage capacities include 120GB, 256GB, 512GB, 1TB, and 2TB.

SSDs are also prohibitively expensive. Prices have dropped significantly in recent years (though they remain higher when compared to HDDs), but this was not the case a few years ago.

Due to their high cost and small storage capacity, SSDs are primarily used as boot-up devices, storing the operating system and other applications, while a secondary HDD is frequently used for storing large files. When SSDs are used as boot-up drives, they significantly reduce boot time when compared to HDDs.

Advantages

• Extremely fast
• Reliable and durable (as there are no moving parts)

Disadvantages

• Very expensive
• Small storage sizes

NVMe Drives

As previously stated, NVMe drives are still solid state drives in the sense that they use solid state semiconductors to store data. However, the interface technology distinguishes SATA SSDs from NVMe drives.

Despite being significantly faster, SATA SSDs are limited to the same 6Gb/s transfer limit as HDDs. This is a limitation of the SATA interface rather than the SSDs themselves.

To overcome SATA’s limitations and unleash the full potential of SSDs, a new interface based on the PCIe interface is being developed (the fastest possible interface between a CPU and an external device apart from the RAM). This interface is known as the Non-Volatile Memory Host Controller Interface Specification, or simply NVMe (NVM Express).

This interface was designed specifically for solid-state devices, and transfer speeds can range between 32GB/s (or 4GB/s for PCIe 3.0 x 4 link) and 64GB/s (or 8GB/s for PCIe 4.0 x 4 link).

With such fast transfer rates comes a low price. NVMe drives are significantly more expensive than SATA SSDs. Despite their high cost, NVMe drives are gradually gaining popularity for their fast read/write speeds in demanding workloads such as gaming, video editing, and other intensive tasks. M.2 NVMe slots are now available in laptops and mini-PCs.

M.2 and, in particular, M.2 2280 are popular form factors for NVMe drives. It’s worth noting that SATA SSDs are also available in M.2 form factors, but the pins and slots (B Key and M Key) for SATA M.2 and NVMe M.2 drives are different.

Advantages

• Extremely fast, in fact the fastest storage type of all
• M.2 form factors is very minimal for compact builds

Disadvantages

• Very costly