Since the introduction of USB 3.0, making sense of USB marketing names has been a source of frustrations for consumers. This is largely due to the fact that each new USB standard absorbs all previous 3.x specifications and at the same time gives them new monikers. Now that the original USB 3.0 has received two major updates, we are now at USB 3.2. The latest specification brings us four speeds altogether and they are as follows:
- USB 3.2 Gen 2×2 defines data transfer rate at 20Gbps over two lanes at 10Gbps each, hence the name SuperSpeed Plus USB 20Gbps on its official namesake logo. For this speed mode, it requires the use of certified USB-C cables.
- USB 3.2 Gen 2×1 is originally known as USB 3.1 Gen 2 and it provides a single lane of 10Gbps. It can work with either legacy USB 3.0 Type-A or USB-C cables. This mode is also the fastest USB speed that Thunderbolt 3 supports natively.
- USB 3.2 Gen 1×2 takes advantage of dual-lane operation capability of a certified USB-C cable, providing two lanes of 5Gbps. This mode, introduced as part of new specification, boosts 10Gbps transfer rate over a passive USB-C cable of 3m in length. In contrast, the Gen 2×1 mode is limited to cables within 1m in order to maintain optimal signal quality.
- USB 3.2 Gen 1 is basically USB 3.0 that was superseded by USB 3.1 Gen 1. Maximum theoretical data transfer is 5Gbps. It can also work with either legacy USB 3.0 Type-A or USB-C cables.
In real world, we’ve seen first generation USB 3.2 Gen 2×1 (aka SuperSpeed Plus USB 10Gbps) SSD from Sandisk manages to push the real-world performance close to 900MBps (or 7.2Gbps) whereas USB 3.2 Gen 1 (aka SuperSpeed USB 5Gbps) equivalent can reach close to 400MBps (or 3.2Gbps). USB 2.0 is still widely used; it delivers both Hi-Speed and Full-Speed mode that operate at 480Mbps and 12Mbps respectively. (Note: the unit is in bits per second.)
When taken account protocol overheads, latency and flow control, the fastest USB 3.2 Gen 1 device should operate at near 450Mbytes per second whereas a USB 3.2 Gen 2×1 device – in best case scenario – should perform at 1.1Gbytes per second in real-world applications. But your mileage may vary depending on the system. The new Gen 2×2 and 2×1 mode also reduce overhead from 20% to just 3% with the USB 3.2’s new 128b/132b encoding scheme; hence, you see better effective throughput.
Real-world USB 3.2 Drive Benchmark
To illustrate how fast USB 3.2 is in real-world scenarios, we compared 8 recently released USB mass storage devices in the bar graph below. Results are shown in megabytes per second, based on our sequential non-compressible file transfer tests that involve a single 10GB MP4 and a folder of 5GB JPEGs. Current testbed as of this writing is a late-2014 Apple MacBook Pro Retina running Windows 10.
In this comparison, external SSDs – the Samsung T5 and Western Digital My Passport SSD – are undisputedly the performance leaders. Powered by a decent flash controller, both models ideally would do far better at USB 3.2 Gen 2×1 (10Gbps). However, for the sake of this comparison, we kept everything at USB 3.2 Gen 1 as all the other drives can’t go any faster than 5Gbps. If you are interested in running applications directly from external drives, these two won’t disappoint.
The next best performers are the Corsair’s Flash Voyager GS and Kingston’s HyperX Savage 3.1. They are both classified as old-fashioned thumb drives in terms of design and intended use-cases. Without USAP, these aren’t designed to run applications as efficiently as the T5 and My Passport SSD but they are more than adequate for moving large files (e.g. media, ISOs) in bulk, in a timely fashion.
For capacity larger than 1TB, nothing beats hard disk drives. 8TB options shown here managed speed at around 180MB/s. By no means are the Seagate Backup Plus and WD My Book slow; traditional hard disk drives are particularly reliable in long-term archival backup as well as incremental backups that likely demand more storage space consumption.
The slowest and the most compact in this comparison is the mini USB drive sub-category. Expect write performance to be on par with that of USB 2.0 storage. Mini drives like Samsung Fit and Sandisk Ultra Fit are targeted at users who need them to stay plugged to a PC or car audio as a semi-permanent storage. Limited by their diminutive size, these drives aren’t exactly built for speed. Yet they are indispensable if you need quick local storage boost for your PC without needing a major upgrade.
This bar chart is by no means an exhaustive comparison of USB drive speeds but it should give you a fairly good idea how each storage type performs in real-world scenarios. We intend to add more drives as needed. Let us know in the comment below what you would like us to add in this comparison.