How fast is a USB 3.0 external hard drive?

USB 3.0, also known as SuperSpeed USB, was introduced in 2008 as the next evolution of the USB standard. It provides data transfer speeds up to 5 Gbps, nearly 10 times faster than the 480 Mbps speed of USB 2.0. This allowed devices like external hard drives to transfer data much quicker when connected via USB 3.0.

External hard drives became very popular for providing extra storage and backup solutions for computers. They are generally mechanical hard disk drives (HDDs), the same technology used for internal storage, enclosed in a portable external enclosure that connects via USB. Common rotational speeds for external HDDs are 5400 or 7200 RPM.

With the advent of much faster USB 3.0 connections, external hard drives were able to reach speeds closer to their maximum disk read/write speeds when connected to a USB 3.0 port. This provided substantial performance improvements over USB 2.0.

USB 3.0 Overview

USB 3.0, also known as SuperSpeed USB, was released in November 2008 as the next iteration after USB 2.0 1. USB 3.0 represented a major leap forward in performance, with maximum data transfer rates up to 5 Gbit/s, compared to just 480 Mbit/s for USB 2.0. This allowed for drastically faster transfer speeds for external storage devices and peripherals.

Some of the key improvements in USB 3.0 over its predecessor USB 2.0 included:

  • Higher maximum bus power – up to 900 mA increased from 500 mA
  • A new transfer mode – SuperSpeed for faster data transfer
  • Full-duplex communication – two-way simultaneous data flow
  • Increased bandwidth – up to 5Gbps, over 10 times faster than USB 2.0

These changes allowed USB 3.0 enabled devices to transfer large files and stream HD video far more quickly and efficiently.

USB 3.0 Speed

USB 3.0 has a theoretical maximum transfer speed of 5 Gbps (gigabits per second), which translates to 640 MB/s (megabytes per second) (Macworld). This is a huge jump from USB 2.0’s maximum speed of 480 Mbps or 60 MB/s.

However, real-world USB 3.0 speeds are lower than the maximum due to overhead and other factors. Benchmarks typically show USB 3.0 with speeds around 400 MB/s for reads and 200 MB/s for writes (PCWorld).

Speed can be affected by the USB controller and drivers, the type of device connected, cable quality, interference, and other factors. USB 3.0 will not achieve maximum speed for all devices and use cases.

External Hard Drive Overview

An external hard drive is a portable data storage device that can be attached to a computer using a USB cable or other connection method. External hard drives serve several key purposes:

  • Provide expanded storage capacity beyond a computer’s internal drive
  • Allow for data backups and transfers between devices
  • Offer a physical backup in case of system failure or data loss
  • Enable large amounts of data to be accessed and transported conveniently

There are two main types of external hard drives:

  • HDD (hard disk drive) – relies on spinning disks coated with magnetic material to store data; tends to be larger and less expensive per gigabyte
  • SSD (solid state drive) – uses flash memory with no moving parts; typically smaller, faster, and more durable but pricier

External hard drives come in a wide range of storage capacities to suit different needs. Standard consumer models may offer 500GB to 5TB, while larger professional versions can store 10TB or more. When choosing capacity, it’s best to consider current storage needs plus expected growth in the future.

According to https://www.seagate.com/support/kb/why-does-my-hard-drive-report-less-capacity-than-indicated-on-the-drives-label-172191en/, actual usable capacity is lower than advertised due to different measurement methods and space used by formatting and computer operation.

USB 3.0 External Hard Drives

USB 3.0 external hard drives offer much faster data transfer speeds compared to older USB 2.0 drives. Some of the most popular USB 3.0 external hard drive models include:

  • Seagate Backup Plus Portable
  • WD My Passport
  • LaCie Rugged Mini
  • Samsung T5 Portable SSD

In speed tests, USB 3.0 external HDDs can achieve real-world transfer speeds of over 100 MB/s for large file transfers. According to tests by PCMag, the 5400 RPM LaCie Rugged Mini achieved write speeds of 101.5 MB/s, while the 7200 RPM WD My Passport managed 113.5 MB/s write speeds. High-performance portable SSDs like the Samsung T5 can reach speeds over 300 MB/s.

In reviews, USB 3.0 external hard drives consistently offer much faster file transfer speeds compared to USB 2.0 drives. For example, Tech Gear Lab found the USB 3.0 Seagate Backup Plus Portable to have over 3x the read and write speeds of the Western Digital USB 2.0 My Passport drive.

Real-World Speed Tests

In real-world tests, USB 3.0 external hard drives generally achieve transfer speeds of 100-200 MB/s for both reads and writes. However, speeds can vary significantly depending on the drive, enclosure, cable, and other factors. Here are some benchmark results:

Testing by Macworld found that on average, USB 3.0 external SSDs had read speeds around 400 MB/s and write speeds around 300 MB/s. Meanwhile, external mechanical hard drives averaged around 120 MB/s for both reads and writes [1].

Toms Hardware saw a wide range of speeds in their testing of 27 external hard drives. The fastest mechanical drive reached 174 MB/s reads and 168 MB/s writes. Most drives achieved between 100-150 MB/s. The slowest mechanical drive managed just 81 MB/s reads and 75 MB/s writes [2].

In general, USB 3.0 mechanical hard drives can reach about 110-180 MB/s, making them 3-5 times faster than USB 2.0. USB 3.0 SSDs are even faster, but also considerably more expensive. For mechanical drives, performance depends largely on the drive inside the enclosure.

Factors Affecting Speed

There are several factors that can affect the speed of a USB 3.0 external hard drive, including:

Hard Drive Type

The speeds of external hard drives can vary greatly depending on the type of hard disk drive (HDD) inside. Traditional hard drives with spinning disks will have speeds around 100-120 MB/s, while solid-state drives (SSDs) can reach 400-500 MB/s or higher. SSDs have much faster read/write speeds due to flash memory and no moving parts.

Computer/Port

The USB port on your computer plays a big role. USB 3.0 ports are required to reach maximum USB 3.0 speeds of around 5 Gbps. Connecting to older USB 2.0 ports will limit speeds to around 35 MB/s. The type of internal drive/bus in your computer can also bottleneck speeds if it can’t keep up with USB 3.0 transfer rates.

File Types

Transfer speeds will vary based on the size of files and how they are arranged on the drive. Large contiguous files will see faster transfer rates than lots of small files scattered on the disk. Compressed files may transfer faster than uncompressed files as well.

Fragmentation

Like any hard drive, fragmentation on the external drive can significantly slow down read/write speeds. Periodically defragmenting the drive can help improve performance.

Use Cases and Recommendations

USB 3.0 external hard drives are ideal for storing and working with large media files due to their fast transfer speeds. The fast data transfer rate allows users to quickly move media files on and off the drive. This makes USB 3.0 external hard drives excellent for photographers, videographers, audio engineers and editors who routinely work with high-resolution photos, HD video footage and other large files.

External hard drives are also commonly used for performing backups of a primary computer or storage system. The large capacities available on external drives make them well-suited for complete system backups. The portability also allows users to store backups offsite for protection against theft or disasters. USB 3.0 provides fast backup and recovery times compared to older USB interfaces.

USB 3.0 external hard drives are also great for simply expanding the storage capacity of a computer or gaming console. The plug-and-play connectivity makes it easy to instantly add terabytes of additional storage space. This provides more room for growing photo libraries, video collections, downloaded games and applications.

According to sources like B&H Photo Video, USB 3.0 external HDDs are recommended for the fast transfer speeds, high capacity, and portability. Key uses highlighted include storage for large media files, backups, and expanding storage for media editing and gaming.

Future Outlook

Faster versions of USB are on the horizon that will offer even higher speeds for external hard drives. Some key advancements include:

USB 3.1, first released in 2013, offers speeds up to 10Gbps. This is double the speed of USB 3.0. External SSDs are starting to leverage USB 3.1 for improved performance. https://tripplite.eaton.com/products/usb-connectivity-types-standards

USB 4.0 was released in 2019 and offers up to 40Gbps transfer speeds by building on the Thunderbolt 3 protocol. USB 4.0 will become more common on high-performance external storage devices like portable SSDs. https://www.cuidevices.com/blog/the-history-of-usb-standards-from-1-to-usb4

Thunderbolt 3, introduced in 2015, set a new benchmark with throughput up to 40Gbps. As Thunderbolt 3 gets adopted, external drives will approach the speeds of internal PC storage. https://www.onlogic.com/company/io-hub/usb-type-c-and-usb-3-1-explained/

Conclusion

In summary, USB 3.0 external hard drives have an impressive real-world transfer speed range of roughly 150-200 MB/s for read and write operations. While the peak theoretical speed of USB 3.0 is 5 Gbps (or 625 MB/s), actual transfer rates are limited by the hard drive itself and factors like file size and system overhead. For smaller files under 50MB, you may see reduced speeds around 50-60 MB/s. Overall though, USB 3.0 drives offer a major speed boost over USB 2.0, with nearly 10 times faster transfer rates. This makes them perfect for tasks like backing up data, editing media files, gaming, and more. Going forward, newer technologies like USB 3.1 Gen 2 and USB4 will push speeds even higher. But for now, USB 3.0 strikes a great balance between price and performance for external storage.