From d9d9c4a749271d419e16754395a44f329d26caba Mon Sep 17 00:00:00 2001 From: Daniel Kraus Date: Sun, 19 Apr 2026 13:36:37 +0200 Subject: [PATCH] Blog post about CFexpress card and disk speeds. Also updates hermit-v2 theme... --- content/posts/2026/disk_speeds/index.md | 110 ++++++++++++++ .../posts/2026/disk_speeds/speed_tests.svg | 137 ++++++++++++++++++ themes/hermit-v2 | 2 +- 3 files changed, 248 insertions(+), 1 deletion(-) create mode 100644 content/posts/2026/disk_speeds/index.md create mode 100644 content/posts/2026/disk_speeds/speed_tests.svg diff --git a/content/posts/2026/disk_speeds/index.md b/content/posts/2026/disk_speeds/index.md new file mode 100644 index 0000000..3e47000 --- /dev/null +++ b/content/posts/2026/disk_speeds/index.md @@ -0,0 +1,110 @@ +--- +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 \ No newline at end of file diff --git a/content/posts/2026/disk_speeds/speed_tests.svg b/content/posts/2026/disk_speeds/speed_tests.svg new file mode 100644 index 0000000..69cb00f --- /dev/null +++ b/content/posts/2026/disk_speeds/speed_tests.svg @@ -0,0 +1,137 @@ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +0.307 GB/s +0.542 GB/s +4.772 GB/s +0.664 GB/s +0.661 GB/s + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +0.311 GB/s +0.343 GB/s +2.993 GB/s +0.485 GB/s +0.406 GB/s + + + + + + + + + +write + + + + + + + + + +read + + +0 +2 +4 +6 +internal_ssd +pgytech_cfexpress +pgytech_cfexpress_direct +ugreen_cfexpress +ugreen_cfexpress_direct +internal_ssd +pgytech_cfexpress +pgytech_cfexpress_direct +ugreen_cfexpress +ugreen_cfexpress_direct +Speed (GB/s) +File size: 1 GB +Sequential read and write speeds + + + diff --git a/themes/hermit-v2 b/themes/hermit-v2 index 5920c3d..3835c6b 160000 --- a/themes/hermit-v2 +++ b/themes/hermit-v2 @@ -1 +1 @@ -Subproject commit 5920c3da938517f0ec37d0c723f0e7c259bba860 +Subproject commit 3835c6bc76c4f62e31a5e494f240b41a7033c848