2023-12-13 20:30:24
We talked regarding it recently, USB4 offers better speeds than the different iterations of version 3.x of the standard, and even exceeds Thunderbolt 3 (or 4). And this development should (finally) become more widespread in 2024, with the arrival of Phison on this market.
Phison talks regarding CES 2024.
To fully understand this new feature, we need to talk numbers: USB 3.x essentially exists in three variants. The original version allows a throughput of 5 Gb/s (500 MB/s maximum, due to the coding chosen, 440 MB/s at best in practice) and is sometimes called USB 3.2 Gen. 1. The second evolution, noted USB 3.2 Gen. 2, allows 10 Gb/s (around 1,200 MB/s, the coding is not the same, around 1 GB/s in practice) and the third, USB 3.2 Gen. 2×2, goes up to 20 Gb/s (roughly 2 Gb/s) but is not compatible with Macs.
The more modern USB4 has two advantages: a speed of 40 Gb/s (4 Gb/s in theory, around 3.2 Gb/s in reality) and very wide compatibility. USB4 devices actually work with different iterations of the USB standard (you can technically plug them into a 1998 iMac) but also in Thunderbolt mode.
A compact, low-cost chip
The chip announced by Phison, which is expected to be presented at CES, is a UFD-type controller, a technology we talked regarding when testing Transcend’s “keys.” The PS2251-21 (U21) (its little name) in fact brings together in a single chip a USB4 controller and everything necessary to support flash memory in an external SSD or even a (large) USB key. This is an interesting development: the only USB4 chip currently used (as at OWC), the Asmedia ASM2464PD, is only a USB4 controller. With the latter, it is therefore necessary to integrate two components (the USB4 chip and the SSD controller) while Phison’s solution is limited to a single chip.
Phison announces theoretical speeds of 4 GB/s, but even if manufacturers integrate slower memory, USB4 brings an advantage over Apple Silicon Macs (USB4 compatible): the possibility of exceeding 1 GB/s. Because as Apple does not support USB 3.2 Gen. 2×2, there is a “hole” in the ranges: compatible models such as the Crucial X10 Pro are blocked at 1 GB/s and you have to upgrade to much more expensive external SSDs to cross this limit.
USB4 finally arrives: test of the ZikeDrive case, for a faster external SSD
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