If you are travelling and you need a storage device that can store up to 7 GB what will you prefer

If you bought an ultraportable laptop anytime in the last few years, you very likely got a solid-state drive (SSD) as the primary boot drive. Bulkier gaming laptops have moved to SSD boot drives, too, while only a subset of budget machines still favor hard disk drives (HDDs). The boot drives in prebuilt desktop PCs are mostly SSDs now, too, except in the cheapest models. In some cases, a desktop comes with both, with the SSD as the boot drive and the HDD as a bigger-capacity storage supplement.

If you have to pick just one, though, how do you choose? Let's get into the differences between SSDs and HDDs, and walk you through the advantages and disadvantages of each to help you decide.

HDD and SSD Explained

The traditional spinning hard drive is the basic non-volatile storage on a computer. That is, information on it doesn't "go away" when you turn off the system, unlike data stored in RAM. A hard drive is essentially a metal platter with a magnetic coating that stores your data, whether weather reports from the last century, a high-definition copy of the original Star Wars trilogy, or your digital music collection. A read/write head on an arm (or a set of them) accesses the data while the platters are spinning.

An SSD performs the same basic function as a hard drive, but data is instead stored on interconnected flash-memory chips that retain the data even when there's no power flowing through them. These flash chips (often dubbed "NAND") are of a different type than the kind used in USB thumb drives, and are typically faster and more reliable. SSDs are consequently more expensive than USB thumb drives of the same capacities. (See our deep-dive guide to SSD jargon.)

Like thumb drives, though, SSDs are often much smaller than HDDs and therefore offer manufacturers more flexibility in designing a PC. While some can install in traditional 2.5-inch or 3.5-inch hard drive bays, other models can be installed in a PCI Express expansion slot or even be mounted directly on the motherboard, a configuration that's now common in late-model systems. (These board-mounted SSDs use a form factor known as M.2. See our picks for the best M.2 SSDs and get much more info on these multifaceted types of SSDs.)

I’m the deputy managing editor of the hardware team at PCMag.com. Reading this during the day? Then you've caught me testing gear and editing reviews of laptops, desktop PCs, and tons of other personal tech. (Reading this at night? Then I’m probably dreaming about all those cool products.) I’ve covered the consumer tech world as an editor, reporter, and analyst since 2015.

I’ve evaluated the performance, value, and features of hundreds of personal tech devices and services, from laptops to Wi-Fi hotspots and everything in between. I’ve also covered the launches of dozens of groundbreaking technologies, from hyperloop test tracks in the desert to the latest silicon from Apple and Intel.

I've appeared on CBS News, in USA Today, and at many other outlets to offer analysis on breaking technology news.

Before I joined the tech-journalism ranks, I wrote on topics as diverse as Borneo's rain forests, Middle Eastern airlines, and Big Data's role in presidential elections. A graduate of Middlebury College, I also have a master's degree in journalism and French Studies from New York University.

Sometimes called portable storage, external hard drives perform the same tasks as internal HDDs and solid-state drives (SSDs).

How to Choose an External Hard Drive

When choosing an external drive, you just need to think about what type of data you wish to store and how much of that data you will need to back up.

Data storage is an essential part of any PC build. Properly storing and backing up your data can save you from some major headaches if data loss ever occurs. One of the best ways to store data or create backups of your system is using an external hard drive. Backing up your data to an external drive is the safest and quickest way to ensure that no matter what happens to your PC, home, or office, your data will be safely stored on another physical drive.

Just like their internal counterparts, external drives come in different types and sizes. With this external hard drive buying guide, we’ll teach you everything you need to know to choose the right solution for you.

Shop External Hard Drives

What is an External Hard Drive?

Sometimes called portable storage, external hard drives perform the same tasks as internal HDDs and solid-state drives (SSDs). Hard drives, internal or external, are how your PC stores data. Everything from documents and photos to the operating system itself is stored on a hard drive. External hard drives are made to move between multiple machines or locations quickly and often have a small form factor. Do not be fooled by their small size: external hard drives can store tons of information or even back up decades of financial or legal documents.

Internal vs. External Hard Drive

The main difference between internal vs. external hard drives is in how they connect to other devices:

• Internal hard drives always require two connections that must plug into particular places on the motherboard and power supply. Internal drives are often bolted into place and require tools to be removed properly. Internal drives use SATA or sometimes even PCIe connections inside the computer that plug directly into the motherboard. These internal connections are capable of the fastest data transfer speeds available. That is why operating systems and programs are often installed on internal drives.
• External hard drives typically plug in via USB cable, and that is it. Sometimes larger drives can require separate power to be used. However, these days most external drives can take the necessary amount of energy needed on that one USB cable. External drives use USB connections to transfer data between devices. While USB 3.1 is high speed, it is still slower than any internal connection. For these reasons, external drives are best for long-term data storage or transferring files that are too large to fit on a USB flash drive.

What is an External Hard Drive Used For?

So, what exactly is an external hard drive used for? Here are just a few potential uses.

When you need to move more than what a flash drive can handle, there are a few options for transferring data. Cloud-based services often have strict limits on how much data you can upload and can take hours to move a single file. That is where external hard drives come in. External hard drives are available in larger sizes than what flash drives are capable of while still featuring the same plug-and-play technology that makes them easy to use. Transferring large amounts of data using external drives is as simple as loading the device with data, traveling to the destination PC, and plugging the drive in.

Important data from work projects and school assignments to family photos and more is stored on a computer these days. Cloud-based backups exist but come with costly fees or subscription plans limiting how much data you can store with them. Having everything in one place is great for convenience but possibly detrimental in terms of potential data loss. Suppose you store backups of your data on an external drive. In that case, you have a duplicate of your information that can be used if your main drive ever fails or becomes damaged.

External hard drives can also be used to securely transfer data. There is zero threat from malicious online-based sources when you use an external physical drive to transfer data. The device itself has no connection to the internet unless connected to a PC. Once data has been transferred to the device, the external drive can be unplugged, and it becomes a miniature safe for your valuable information. The only way to access the data on your external drive is to plug it into another PC and give that computer permission to access the files on your external drive.

These days, all of your most sensitive information and documents are often stored electronically. If you do not have a backup of your valuable information, a single internal hard drive failure could mean losing legal documents, tax returns, birth certificates, and more. External hard drives are perfect for archiving your most critical information because they can safely store duplicates of your data. Physical backups are much more secure than cloud-based solutions because they are offline. When not in use, they are powered off and can be stored in a safe location.

What Size External Hard Drive Do I Need?

The most common sizes for external hard drives are 500GB, 1TB, and 2TB. Some smaller and larger sizes are available as well. The amount of storage capacity does not affect the type of data that can be stored on the hard drive.

• 500GB: Perfect for students or a single-family that needs to store some sensitive documents or transfer data too large to fit on a flash drive.
• 1TB: The most common size of an external hard drive. 1TB is equivalent to 1000GB and is ample space for up to 250,000 photos or nearly 500 hours of HD video.
• 2TB: Becoming more popular as of late, 2TB drives can store massive amounts of high-definition video and high-resolution images. These drives are perfect for professionals or businesses that need to store or transfer large amounts of photos or videos.

How to Choose an External Hard Drive

Now that you know the benefits of external hard drives and their uses, how do you choose the right external hard drive for you?

Choosing an external hard drive can feel like choosing a computer all over again. Luckily there are not nearly as many specifications or terms to remember. When choosing an external drive, you just need to think about what type of data you wish to store and how much of that data you will need to back up:

• File Size: Documents and files, for instance, take up minimal space. If that's all you are keeping, a 500GB external hard drive will be more than enough space. Suppose you like to take photos or do any video recording or game capture. In that case, you will probably want to buy a 1TB or larger external drive to archive all your videos.
• Portability: Sometimes, portability might be the most crucial factor, and for that, a smaller external drive that derives power from a USB cable might be more fitting.

No matter which external hard drive you choose, they will all be able to store and backup your data safely.

Types of External Hard Drives

There are a few different types of external hard drives from which you can choose. Sometimes, specific drives can be needed depending on how much data you need to back up, or if you plan to be traveling with the external drive often. Below are some of the most common types of external drives and some information about them:

• 2.5”: Smaller in size and storage capacity than larger 3.5" drives, 2.5" drives are ideal for traveling or storing data that needs to be moved from location to location frequently.
• 3.5”: While larger 3.5" drives come with more storage space and sometimes faster data transfer speeds, the larger form factor is not without its flaws. 3.5" external hard drives often require dedicated power connections or are quite large in design and can be heavy or fragile when traveling.
• Powered: Some external storage requires a separate power connection along with the USB connection to the PC to function. This is often because of the large capacity or high transfer speeds of the external hard drive. 
• Portable: External hard drives that only use one cable for power and transferring data are considered portable storage. These drives are perfect for students or professionals who need to move large amounts of data between machines frequently. The single cable makes the device easy to use and comfortable to travel with.

No part of your PC is more important than your data. Having the proper backups in place can protect you from losing decades of important files. External hard drives are perfect for backing up or transferring large amounts of sensitive data. When you have a physical backup stored in a separate location, you have a guaranteed duplicate of any information you could lose from your primary device.

External drives are also perfect for students or professionals who need to move large amounts of data that could take hours to upload and download every day. Buying an external drive can seem daunting, but you can refer to this guide at any time to help ensure that you find an external storage device that best fits your needs.

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