110 lines
4.9 KiB
Markdown
110 lines
4.9 KiB
Markdown
---
|
|
title: "Testing CFexpress Type B card readers"
|
|
description: >
|
|
Is there a true, relevant difference in the performance of current CFexpress
|
|
Type B card readers, or is it all just marketing?
|
|
date: 2026-04-19T12:26:06+02:00
|
|
draft: false
|
|
# ShowLastmod: true
|
|
toc: false
|
|
scrolltotop: true
|
|
images: []
|
|
tags:
|
|
- linux
|
|
- photography
|
|
---
|
|
|
|
I've been looking for a card reader for my CFexpress Type B cards that I use in
|
|
my camera. There are not very many devices on the market, but they have a large
|
|
price span: around 10x.
|
|
|
|
Since I was wondering whether the price correlates with speed, I decided to
|
|
perform some simple tests using my existing hardware:
|
|
|
|
- a UGREEN CFexpress Type B card reader
|
|
- a PGYTECH CreateMate CFE-B/SD card reader
|
|
- a Nextorage B1 Pro CFexpress Type B card with 165 GB capacity
|
|
- the built-in NVMe SSD of my Thinkpad laptop, a Samsung SSD 990 PRO with 2 TB
|
|
storage capacity.
|
|
|
|
The two external card readers are attached via USB-C/USB 3.2 Gen 2 to my
|
|
Thinkpad Thunderbolt 3 dock. I am generally happy with both of them, I think
|
|
they have good quality.
|
|
|
|
By the way, why should I even look for a new card reader in the first place?
|
|
Well, the CreateMate card reader is a bit bulky and heavy and I once forgot to
|
|
take it with me on vacation. So I was looking for something smaller and lighter.
|
|
|
|
## Sequential read and write tests
|
|
|
|
I did not want to overcomplicate things, just get an impression if there are any
|
|
differences between card readers or not. Therefore I decided to perform
|
|
sequential read and write tests using `dd` as described at [Baeldung.com][].
|
|
|
|
The graph below shows the means and standard deviations of 5 tests for each
|
|
device. The "direct" label denotes tests with the card reader attached directly
|
|
to a USB-C/USB 3.2 Gen 2 port of my [Thinkpad P14s][] laptop, rather than via
|
|
the Thunderbolt 3 dock.
|
|
|
|
{{< figure src = "speed_tests.svg" >}}
|
|
|
|
When attached to the Thunderbolt dock, the PGYTECH CreateMate reads from the
|
|
CFexpress card much faster than the UGREEN reader. It does also write a bit
|
|
faster than the UGREEN reader.
|
|
|
|
Attaching the card readers directly to the laptop results in increased speeds
|
|
overall, and the differences between the UGREEN and the PGYTECH readers seems
|
|
negligible.
|
|
|
|
**However, regardless of how the readers are connected to the laptop, both are
|
|
left in the dust by the internal SSD!**
|
|
|
|
Is the observed difference in read speeds between the UGREEN and the PGYTECH
|
|
card readers "clinically relevant"? Does it justify spending a lot more money
|
|
for the PGYTECH reader? Given the very large difference of both of these card
|
|
readers to the internal SSD, I don't really think so.
|
|
|
|
## What to expect from a "USB-C" or rather, USB 3.2 Gen 2 connection
|
|
|
|
It should be noted that the USB 3.2 Gen 2 standard has a nominal transfer speed
|
|
of 10 GBit/s or 1.25 GB/s. As stated in the [Wikipedia article on USB 3.2][],
|
|
actual transfer rates are round 0.8-1.0 GB/s. Still higher than what I measured.
|
|
|
|
My Thinkpad's USB-C ports a really Thunderbolt 4/USB 4 ports that should be
|
|
capable of transferring up to 40 Gbit/s or 5 GB/s. This would be in the internal
|
|
SSD's ballpark. However, the card readers have "only" USB 3.2 Gen 2. PGYTECH
|
|
claims 1000 MB/s for the CreateMate and UGREEN 1250 MB/s for their device. The
|
|
card itself claims read speeds of up to 1950 MB/s and write speeds of up to 1900
|
|
MB/s, which roughly corresponds to 1.86 and 1.90 GB/s. Obviously, the 0.3 to 0.6
|
|
GB/s that I measured are nowhere near any of these numbers.
|
|
|
|
## Using Darktable's local copies feature
|
|
|
|
Evidently, nothing is faster than the internal NVMe SSD.
|
|
|
|
This reminds me that [Darktable][] has a feature to copy image files to the
|
|
built-in SSD. This not only allows for faster read and write speeds, but also
|
|
makes it possible to work on the images without having the card reader attached
|
|
to the laptop: [Darktable's user manual on local copies][local-copies].
|
|
|
|
Local copies (or rather, the XMP sidecar files) are synchronized whenever the
|
|
external storage is attached when Darktable is starting up. I don't know if
|
|
Darktable will automatically remove synchronized local copies in case disk
|
|
space gets low.
|
|
|
|
## Conclusion
|
|
|
|
In practice, I am going to create local copies of my images and select and work
|
|
on the local copies. Yes, the initial process of copying the files will take a
|
|
few seconds less with the PGYTECH reader than with the UGREEN reader, but that
|
|
is negligible given the amount of time that I spend on selecting the images and
|
|
working on the RAW file development in total.
|
|
|
|
Therefore, if I decide to purchase a new reader, I will focus on the size and
|
|
build, and the UGREEN reader is a strong contender when it comes to small size.
|
|
|
|
[baeldung.com]: https://www.baeldung.com/linux/disk-performance-test
|
|
[darktable]: https://darktable.org
|
|
[local-copies]: https://docs.darktable.org/usermanual/development/en/overview/sidecar-files/local-copies/
|
|
[Thinkpad P14s]: {{< relref "p14s" >}}
|
|
[Wikipedia article on USB 3.2]: https://en.wikipedia.org/wiki/USB_3.0#3.2 |