Can I use flash drive as hard drive?

What is a Flash Drive?

A flash drive, also known as a USB flash drive, USB drive, USB stick, or thumb drive, is a small, lightweight, removable, and rewritable data storage device (Delkin). It contains flash memory with an integrated USB interface that connects directly to the USB port on a computer or device. Flash drives are portable, fast, easy to use, and store data without needing power like an internal hard drive (Merriam-Webster).

Most flash drives come in capacities between 8GB to 512GB, though smaller 1GB and larger 1TB+ drives are available. Their small size, typically a few inches long and less than an inch wide, makes them extremely portable and convenient for transferring files between devices and carrying data on the go (Wikipedia).

The main benefits of a flash drive are portability, ease of use, speed, and rewritability. Flash drives don’t require external power and are plug-and-play. The downsides are their limited capacity compared to external hard drives, lower reliability and higher cost per gigabyte of storage (Wikipedia). Overall, flash drives excel at quickly transferring files between devices, conveniently backing up data on the go, and transporting documents without needing large or powered enclosures.

What is a Hard Drive?

A hard disk drive (HDD) is a electro-mechanical data storage device that uses magnetic storage to store and retrieve digital data. HDDs consist of one or more rigid platters coated with magnetic material and spindle motor that rotates the platters. A read/write head on an arm assembly reads and writes data to the platter surfaces.

HDDs come in a range of storage capacities from hundreds of gigabytes to tens of terabytes, with higher capacity models continuing to be developed. HDDs can be either internal, meaning they are installed inside a computer case and connected directly to the motherboard, or external, meaning they connect to the computer via a cable like USB or Thunderbolt.

The key advantages of HDDs are their large capacities for storing huge amounts of data, low cost per gigabyte compared to solid state drives, and mechanical reliability over years of operation. Drawbacks include slower read/write speeds than SSDs, larger physical size and weight, noise from spinning platters, heating, and greater shock sensitivity.

Speed Comparison

Flash drives typically have faster read speeds but slower write speeds compared to hard drives. According to benchmarks, high-end USB 3.0 flash drives can achieve read speeds of around 150-180 MB/s and write speeds of 70-100 MB/s (Source: Reddit). In comparison, a 7200 RPM desktop hard drive has sustained transfer speeds of around 80-160 MB/s for both reads and writes.

The main advantage of flash drives is very fast access times, usually under 1 ms, which allows quick lookups of small files. Hard drives have typical access times of 10-15 ms due to physical limitations of moving drive heads (Source: SuperUser). So for large sequential transfers, hard drives are faster, but for small random file access, flash drives are faster.

Bandwidth is also a limiting factor – USB 3.0 theoretical maximum is 625 MB/s, while SATA interfaces on hard drives can reach speeds of 600 MB/s. So the interface and connector standards limit real-world transfer speeds for both devices (Source: Quora).


When it comes to reliability and lifespan, external hard drives tend to outperform USB flash drives. Hard disk drives have moving parts like spindle motors and actuator arms that can fail over time, but the average lifespan is around 3-5 years under normal use (External Hard Drive vs. USB Flash Drive). SSDs can last even longer, with a typical lifespan of 5-10 years (External Hard Drive vs Flash Drive).

USB flash drives have no moving parts, but the NAND flash memory chips inside have a limited number of write cycles before they start to fail. A high quality flash drive used moderately may last 5+ years, but heavy usage can significantly reduce the lifespan to less than 1 year (Are Flash Drives Reliable?). The controller electronics can also fail over time.

Overall, external hard drives and SSDs are designed for more frequent writing and have longer rated lifespans than flash drives. For storing important data long-term or running operating systems and applications, HDDs and SSDs are a safer bet (Can a flash drive be used as an external hard drive). But flash drives are more portable and convenient for transferring files.

Use Cases

When choosing between a flash drive or an external hard drive, it’s important to consider the use case. Flash drives are best for portable storage and transferring files between devices. Their small size makes them easy to carry around. Flash drives are good for everyday documents, photos, music and other media that don’t require a lot of storage space. However, they lack storage capacity compared to external hard drives.

External hard drives excel at expanded storage and backing up large amounts of data. With storage sizes upwards of 4TB, external hard drives can hold entire digital libraries of documents, photos, videos, games and software installers. They can create full system backups. External hard drives are ideal for additional storage at home or work when the internal drive capacity isn’t enough. Photographers, videographers, graphic designers and gamers often use external hard drives to store their large files.

In summary, flash drives are better for quickly transferring smaller files and external hard drives are preferred for expanding long-term storage and backups. If portability is the priority, a flash drive is the way to go. But for sheer storage capacity and constant use, an external hard drive is superior.

Cost Comparison

When looking at price per gigabyte, flash drives tend to be more expensive than external hard drives, especially for higher storage capacities. This is because flash drives have smaller physical size and lower production costs compared to external hard drives.

For example, a 128GB flash drive may cost around $20, while a 1TB external hard drive costs around $50. That means the flash drive costs around $0.16 per GB, while the hard drive costs around $0.05 per GB. The larger the storage capacity, the wider this price gap becomes.

Factors like brand, performance, form factor, and other features will also affect the price. But in general, external hard drives provide more storage capacity per dollar compared to flash drives. This makes them more cost effective for large storage needs.

According to, “Flash drives tend to be more expensive on a per-gigabyte basis compared to external hard drives, especially for higher capacities.” [1] This price difference is a key consideration when choosing between the two for backup or expanded storage purposes.


When it comes to security, there are some important differences between flash drives and external hard drives to consider. One major factor is encryption – many external hard drives come with built-in encryption or the ability to encrypt the drive, while encryption is less common on flash drives. Encryption helps protect the data if the drive is lost or stolen. According to Stack Exchange, full disk encryption is more feasible on a hard drive than a flash drive.

Another consideration is vulnerability to malware. Because flash drives are often plugged into many different devices, they can more easily pick up malware or viruses and spread them from computer to computer. External hard drives pose less of a malware risk if dedicated to a single computer. Proper scanning and protection software on both devices is important.

Overall, external hard drives tend to offer stronger security protections through built-in encryption options. But both external drives and flash drives require users to practice safe computing habits to minimize security risks.


Flash drives generally have very wide compatibility across operating systems and devices. Most flash drives use common formats like FAT32 or exFAT that allow them to be read and written to by Windows, Mac OS, Linux, Chrome OS, Android, and iOS devices. According to Flash Drives vs. Thumb Drives, “Most thumb drives are formatted as FAT32, right out of the box.”

Hard drives may have more limited compatibility depending on the interface used. For example, an older IDE or SATA hard drive would not work with newer USB-C only devices without an adapter. However, external USB hard drives have very wide compatibility similar to flash drives across many operating systems. According to Do all hard disk drives (HDDs) need to be USB compatible, external hard drives connect via USB so they can be used with many devices.

Overall, both flash drives and external hard drives tend to have excellent compatibility nowadays across computers, phones, tablets, and other devices. Flash drives may have a slight edge for OS support, while hard drives are now comparable when connecting externally via USB.


When it comes to expanding storage capacity, hard drives are much more upgradable than flash drives. Hard drives have more capacity options available, from a few hundred gigabytes up to tens of terabytes. SSDs are also available in large capacities, but are currently far more expensive per gigabyte than HDDs. With a hard drive, you can easily swap in a new higher capacity model to upgrade your storage.

In contrast, most flash drives max out at 1-2TB of storage. To upgrade, you would need to purchase an entirely new flash drive, rather than just swapping out an internal component like you can with a hard drive. Additionally, hard drives allow you to add more storage via external drives or in some cases additional internal hard drives. With flash drives, expanding storage capacity beyond the fixed internal capacity is not really possible. Ultimately, hard drives provide more flexibility for storage upgrades. Source


While USB flash drives can technically function as external storage and even boot drives, they are not ideal for long-term or intensive use as a primary hard drive.

The biggest drawbacks of using a flash drive as a hard drive are the limited lifespan, slower speeds for reading and writing data, and lack of security features. Most experts advise against relying on flash drives for your operating system or program files.

For short-term, temporary storage and transfer of files between devices, flash drives serve their purpose well. But for day-to-day computer use, an external hard drive or SSD is preferable over a flash drive.

Solid state drives provide the best combination of speed, reliability, and lifespan for external storage today. While more expensive than flash drives, SSD prices have dropped steadily in recent years.