Writing to external flash - too slow?https://devzone.nordicsemi.com/f/nordic-q-a/83205/writing-to-external-flash---too-slowHi again Nordic. I&#39;m trying to write sensor data to the external flash continuously as there is not enough RAM to hold all the data required. However, the writing operation is too slow and data gets lost. I&#39;m getting 4000 64-bits int every second fromen-USTelligent Community 13Thu, 13 Jan 2022 11:14:29 GMTRE: Writing to external flash - too slow?https://devzone.nordicsemi.com/thread/347560?ContentTypeID=1Thu, 13 Jan 2022 11:14:29 GMT137ad170-7792-4731-bb38-c0d22fbe4515:667e96e5-b846-425e-8ea1-ef702fb48a42nWre<p>Hi! Yes, I got an sd-card reader working and the write speed is very good. However, there is a delay when the data being written exceeds the cluster size(in my case 4096 bits). I&#39;m currently working on this as the delay is so small it doesn&#39;t occur everytime. My databuffer overflows after 23ms so the resizing after exceeding cluster must be less than that and right now it&#39;s between 20-24 ms but not consistent. Maybe that deserves its own thread and it might be a more generic problem with fat32 and zephyr than nordic. I guess this can be closed with the conclusion: SD-cards are faster than the external flash when writing data.</p><div style="clear:both;"></div>RE: Writing to external flash - too slow?https://devzone.nordicsemi.com/thread/347496?ContentTypeID=1Thu, 13 Jan 2022 07:24:05 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f3061e76-fcd1-448d-bbba-d4de3b0147b6Simon<p>Hello, sorry for the delay on this. I did not get any answer internally unfortunately. Be aware that SPI is slower than QSPI (which was used in the ticket you linked to)</p> <p>So I will take a closer look at this myself. It seems like you&#39;re going for an SD-card:&nbsp;<a href="https://devzone.nordicsemi.com/f/nordic-q-a/83552/sd-card-on-nrf9160dk">https://devzone.nordicsemi.com/f/nordic-q-a/83552/sd-card-on-nrf9160dk</a>&nbsp;</p> <p>Have you got any progress?</p><div style="clear:both;"></div>RE: Writing to external flash - too slow?https://devzone.nordicsemi.com/thread/346470?ContentTypeID=1Thu, 06 Jan 2022 12:40:27 GMT137ad170-7792-4731-bb38-c0d22fbe4515:b0881d6d-8ba7-47d1-95cc-6c8389110b05Simon<p>I did a test with the nRF9160DK (write speed of littlefs--&gt;spi_nor--&gt;spi--&gt;<span>mx25r6435f</span><span>&nbsp;</span>) and measured a speed of 0.0255MB/s. I&nbsp;have asked a developer internally if there is any ways to improve this or if you need to use an alternative solution. I will get back to you if I get any replies.</p><div style="clear:both;"></div>RE: Writing to external flash - too slow?https://devzone.nordicsemi.com/thread/345692?ContentTypeID=1Mon, 03 Jan 2022 14:10:21 GMT137ad170-7792-4731-bb38-c0d22fbe4515:856370e3-6a81-4276-ade2-ef2d6e495db3nWre<p>No worries, the amount of questions I&#39;m throwing your way would warrant vacation for the whole team :) I&#39;m trying out an sd-card in the meantime and will update the thread accordingly.</p><div style="clear:both;"></div>RE: Writing to external flash - too slow?https://devzone.nordicsemi.com/thread/345555?ContentTypeID=1Sun, 02 Jan 2022 20:42:47 GMT137ad170-7792-4731-bb38-c0d22fbe4515:e7632118-2c6e-4653-bae4-2b0475c693a6Simon<p>Hello, sorry for the delay on this. A huge part of the support team has been on vacation, but we will look into it the next week</p> <p>Best regards,</p> <p>Simon</p><div style="clear:both;"></div>