LinuxMusicians

@trawglodyte asked me about external USB4 speeds and I thought I'd share this with you.
This might be of use to somebody and I hope it's easier to find in this subforum.

I got myself a new PC and an external USB4 SSD enclosure.

my tldr experience:

• check the effective possible speed to save money on the SSD itself

• cables matter

• an actively cooled enclosure is helpful if you expect longer/bigger transfers

Speed calculations
USB4 (first version) supports 40 Gbps, i.e. 5,000 MB/s
The protocol overhead is said to be about 15%. Subtract from theoretical maximum: 5,000 MB/s - 750 MB/s = 4,250 MB/s.
We can expect up to ~ 4,250 MB/s then.
So no need to go shopping for the latest Gen5 SSD. A solid Gen4 SSD might suffice, even a fast Gen3 SSD might be all you need for your use case.

The case itself
I bought an actively cooled NVMe SSD metal case. It has a small fan spinning.
Yes, it is noisy when under sustained load. But I can keep max speeds over longer periods this way (e.g. when transferring large backup files to the external drive).

The surprise: cables really matter.
My case came with an included USB4 cable. How nice!
It got me to about 1940 MB/s read speeds. Which is nice in itself, but...
...with a "good" cable, under otherwise identical conditions, got me 3850 MB/s. That's nearly doubled!

And here are my 2 screenshots of the benchmark with included cable and "certified USB4 40 Gbps for EUR 20" cable:

Hope this helps you!
Any questions, let me know

In all the excitement, I forgot about write speeds.
In synthetic benchmarks, I get about 400 MB/s.
Real life transfers (think huge backups) get consistent 700 MB/s.

nevis wrote: ↑Thu Jan 25, 2024 8:18 pm

In all the excitement, I forgot about write speeds.
In synthetic benchmarks, I get about 400 MB/s.
Real life transfers (think huge backups) get consistent 700 MB/s.

Thank you!! The reads are mind-bogglingly fast but I was particularly interested in write speeds. With numbers like 20Gb/s, 12,000mb/s and so forth being tossed around people might not think 400-700mbs is impressive, but IT IS!! FYI-my 3.1 Gen 1 USB can only write at about 10mbs max.

One thing I'm particularly interested in is lightweight Linux OS's which load into RAM (from a USB) on startup. It's really a great way to have an OS (believe it or not). After such an OS boots up it runs just as well, or better, than an OS on disk. But when you make a save, it can be slow. If I could write to my USB flash drive @400-700mbs keeping an OS on flash drive would really not be inferior to having it on a disk in any way, and have some advantages.

But that aside, just being able to drag and drop a large video file, your music projects, or a .iso or something to a USB flash drive and have it write @400-700mbs would be fantastic!! This is approx. the same speed as the 2.5" SSD's that we thought were incredibly fast just 5 years ago.