Posting the MicroSDXC speed test results for the three memory cards I use in my S1 4K dashcams. They are the:
- Kingston Canvas Go! Plus 512GB
- Kingston Canvas Go! Plus 1 TB
- VUEROID-branded 256GB
Testing was done on my Mac Studio Max M4, using the SDXC card slot ( UHS II ). I could probably achieve slightly faster speeds if using an external card reader.
The testing tool is the Blackmagic Disk Speed Test. For Mac users, you can find the tool in your App Store. Be sure to download the Disk Speed Test; you do not want the available RAW test.
All three cards have been reliable for my use. The Kingston Canvas Go! Plus, for the 1 Terabyte size, it should probably be formatted at least once a month. I did have two system restarts with this card; no video footage was lost. The 1 Terabyte card is not supported. I am pushing the curve a bit by using the 1 TB size, so no complaints, as the S1 4K has handled the 1 TB size and the saved files correctly.
The VUEROID 256GB MicroSDXC card test.
View attachment 87313
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For these next two images, the first is the Kingston Canvas Go! Plus 512GB, the second is the 1 TB.
View attachment 87314 View attachment 87315
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To help you understand, let's take a technical look at SD and dashcams.
1. A dashcam continuously generates data when it's turned on. for example at a bitrate of 40 Mbit, it generates 8 Mbytes per second. If an impact occurs, the previous 10 seconds of data must be written, so this is when the most data needs to be written.
2. SD cards contain embedded NAND flash and a controller. The controller performs tasks such as ECC, wear leveling, garbage collection, and bad block handling. It manages the speed and lifespan of the SD card.
3. SD card speed is not constant. While the average speed is constant, slowdowns are observed at certain moments (due to internal operations such as garbage collection).
4. The reliability of the NAND flash inside the SD card is crucial, especially when it comes to temperature. Most dashcams have high internal temperatures, so caution is advised.
Based on these facts, we conduct extensive software trials and tests.
First, because the speed of the SD card is not constant, prepare sufficient buffer. For example, we reserve a DDR buffer of approximately 15 seconds.
Second, develop a file manager and file system to prevent speed degradation due to increased logical operations caused by fragmentation.
Third, conduct extensive testing. We conduct aging tests that continuously generate artificial events for at least two weeks to check for reboots.
Testing is also performed in high-temperature and low-temperature environments.
If even one reboot occurs during this process, the SD is failed