Will faster micro SD card make my WLAN Pi M4 boot faster?

No, it will not, unless you make some bad choices. But, faster card will make your life easier and significantly speed up the image flashing process.

Tests performed

  • Flash and verify WLAN Pi 3.1.4 software image to the micro SD card using built-in card reader of MacBook Pro M2 and Balena Etcher app
Software image flashing process
  • Boot WLAN Pi M4 from the micro SD card. Measure how long it takes to boot from plugging the Ethernet cable in (and PoE power provided) to WLAN Pi home screen shown on the display
WLAN Pi M4 powered via PoE

Results

Sandisk High Endurance 32 GB U3 card is the default provided with WLAN Pi M4 by default. The U3 standard reall y makes a huge difference when it comes to writing to the card and that’s why it is our go to option.

Micro SD cards tested

From practical perspective, different size or even slightly slower card won’t really make your Pi boot any faster. If you make some bad choices and reuse an older class 6 card, you will spend extra 11 seconds of your life waiting for the WLAN Pi to boot every single time.

Flash WLAN Pi imageEffective speedBoot WLAN Pi M4
Sandisk HE 32 GB U31 min 59 seconds64 MB/s28 seconds
Sandisk HE 256 GB U31 min 53 seconds68 MB/s28 seconds
Sandisk Ultra 32 GB U13 mins 54 seconds24 MB/s28 seconds
Samsung 8 GB Class 611 mins 29 seconds8 MB/s39 seconds
Compute Module 4 with built-in eMMC storageDidn’t testDidn’t test27 seconds

Recommendation

Invest in a U3 or better card and benefit from fast write speeds. There is very little premium to pay. In future, you can reuse a fast card in other device like a dash cam, Raspberry Pi 5 workstation, or video camera.

Kingston has a great blog post about SD card standards.

Published by

Jiri Brejcha

Jiri is passionate about mobility ranging from Wi-Fi to folding bikes;-) He is a Wi-Fi Technical Solutions Architect at Cisco UK, proud member of the Cisco Live Network Operations Center deployment team, and WLAN Pi development team. If he is not working, he is most likely riding his Brompton bike.

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