@ESP_sprite, I did some further tests: - using a class 10 SD card (instead of the class 4 I was speaking above) I get just about a 10-15% speed improvement Following the observations of @gingerologist, the issue seems: - not linked to the SD card (a class 10 is more than twice as fast as a class 4 b...

@ESP_Sprite, thanks for your reply. In the example I posted, I'm writing chunks of 1000 bytes at each call of fwrite. I verified afterwards the output file and it's written correctly. I tried writing chunks of 1024, 4096, 65536 bytes as well and I obtained the same writing speed. To give some more d...

Hello, I just benchmarked the write speed to an SD card and found out that it caps at about 400kB/s. I was surprised of such a low speed and read posts where users claim writing speeds of more than 1MB/s (up to 9MB/s) while others have speeds comparable to mine but could not figure out the differenc...