The Pi, for years, has had a very limited amount of bandwidth, shared amongst all of the above. For a few years, competitors like the Asus TinkerBoard and OrangePi had more dedicated bandwidth to support faster I/O on the network bus, USB ports, and the microSD card reader. I was most excited to see the I/O improvements in the Raspberry Pi 4, which I felt were long overdue. It's often impossible to get that data, which is why I do these now-annual blog posts! Raspberry Pi 4 microSD performance improvements I don't blame the manufacturers here, because probably 90-95% of those buying these cards are not using them as the main system boot volume on a Linux computer, as you and I do :)īut it would be nice to see random I/O metrics somehow reflected in flash card datasheets. Instead of seeing the '95 MB/sec' that's advertised on the front of the Sony microSD card, for example, I found 0.66 MB/s write speed when writing random 4K blocks. But this is with large video data chunks, which are fairly easy to optimize for in cheap mass-produced flash controllers.īut when you look at random 4K I/O (which is 4 kilobyte blocks of data, written to random segments of the flash drive), the performance is vastly reduced. The 'C10' or 'U3' designations typically represent a speed class like '10 MB/sec' or '30 MB/sec' write, respectively. You can also run the benchmark on your own Pi using the following command: curl | sudo bashĮarlier in the post, I mentioned that microSD cards are often marketed based on their maximum throughput. You can find all the raw data, and benchmark methodology (as well as a link to the script used to run the benchmark on the Pi) on the official Raspberry Pi Dramble website: Raspberry Pi microSD Card Benchmarks. but whatever optimizations they do for that performance seem to negatively impact random write performance. Note that these 'super fast' cards are often faster when writing large files or streaming data to/from the cards. Some cards cost a lot more, yet offer less than half the write performance. And it's almost double the best performance of the 2nd place contender, the Samsung Pro+ (which costs a lot more). The Evo+ is one of the lowest-priced microSD cards (less than ten USD on Amazon right now), and it has either the best or near-best performance for every metric. Therefore, before going further, here are the 2019 benchmarks, run on a brand new Raspberry Pi 4 model B (1 GB RAM), using the official Raspberry Pi USB-C power supply:Īs with previous years, and again to get right to the point, here are my recommendations for a microSD card for your Pi: If there's one thing I hate, it's blog posts that require you to read a novel before getting to the meat. And here is where most of even the most expensive microSD cards fall incredibly short. On top of that, the performance metrics used in microSD marketing are usually targeted only at the major market for these tiny memory chips: those who record video and stills on them, and only ever really care about massive file read/write performance.įor general purpose computing-which is what SBCs like the Raspberry Pi do-random I/O performance is much more important. SD cards in general have performance characteristics that pale in comparison to faster devices, like NVMe SSDs, eMMC, and XQD or CFexpress. One thing that is almost universally true (at least as of 2019) is that the most common system boot device is a microSD card. You can search my site for tons of articles on these experiences. I have owned and used every generation of Raspberry Pi, in addition to most of the popular competitors. Note: I also posted a separate review of some A2 'Application Performance' class cards, see this post: A2-class microSD cards offer no better performance for the Raspberry Pi.Īs a part-time tinkerer and full-time developer, I have been fascinated by single board computers (SBCs) since the first Raspberry Pi was introduced almost a decade ago.

Usb 3.0 ssd benchmark