upddate

docs/cfe_card.md

@@ -6,12 +6,65 @@ CFE-TypeB card cost-effective solution.
 
 ![card](/card.jpg)
 
-DIY CFE-TypeB card only needs NVMe SSD + Any CFE-TypeB card holder. My two cards were made in
+DIY CFE-TypeB card only needs NVMe SSD + Any CFE-TypeB card adapter. My two cards were made in
+
 - JEYI 2280 card adapter + Samsung 970 EVO-Plus 2T 
 - ZITAY 2230 card adapter + WD SN740 
 
-They have extremely fast reading and writing speeds, and has very good heat dissipation effect. I recommend the 2230 size, which is easy to carry and will not hinder your shooting when using it. But if you use it for long-term shooting and larger capacity, I recommend the 2280 size.
+They have extremely fast reading and writing speeds.
 
 ## How to make it?
 
-<iframe width="560" height="315" src="https://www.youtube.com/embed/7wKL-6GBSw8?si=lHNireKPicTYYE7-" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
+<iframe width="560" height="315" src="https://www.youtube.com/embed/7wKL-6GBSw8?si=lHNireKPicTYYE7-" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
+
+## Which size should I choose?
+
+I recommend the 2230 size, which is easy to carry and will not hinder your shooting when in use. But if you are shooting for a long time and the capacity is large, I recommend the 2280 size.
+
+Because the 2230 card is shorter and has less exposed parts, the heat dissipation effect is worse than the 2280 card. When the card temperature is too high due to long-term recording, it will slightly affect the CPU usage and writing speed during writing.
+
+The following are the speeds I tested, it will be affected by the SSD, so it is just for reference: 
+
+- 2230
+
+```shell
+# Initial
+
+pi@cinepi:~ $ ./test_speed_multi /media/RAW
+Total data written: 1500 MB
+Time taken: 2.05 seconds
+Write speed: 730.71 MB/s
+User CPU time used: 0.00 seconds
+System CPU time used: 0.04 seconds
+
+# After fever
+
+pi@cinepi:~ $ ./test_speed_multi /media/RAW
+Total data written: 1500 MB
+Time taken: 2.42 seconds
+Write speed: 620.26 MB/s
+User CPU time used: 0.00 seconds
+System CPU time used: 0.04 seconds
+```
+
+- 2280
+
+```shell
+# Initial
+
+pi@cinepi:~ $ ./test_speed_multi /media/RAW
+Total data written: 1500 MB
+Time taken: 2.03 seconds
+Write speed: 740.12 MB/s
+User CPU time used: 0.00 seconds
+System CPU time used: 0.04 seconds
+
+# After fever
+
+pi@cinepi:~ $ ./test_speed_multi /media/RAW
+Total data written: 1500 MB
+Time taken: 2.03 seconds
+Write speed: 737.25 MB/s
+User CPU time used: 0.00 seconds
+System CPU time used: 0.05 seconds
+```