diff --git a/Using-the-SD-Card.md b/Using-the-SD-Card.md
index ec75a93..7aebe3b 100644
--- a/Using-the-SD-Card.md
+++ b/Using-the-SD-Card.md
@@ -58,6 +58,6 @@ When an SD card job is running, the percent complete is appended to the status s
 
 ### Card Formatting ###
 
-The firmware uses the [Arduino SD library](https://www.arduino.cc/en/Reference/SD). This is limited to 4G cards.
+The firmware uses the [Arduino SD library](https://www.arduino.cc/en/Reference/SD). This is limited to 4G cards. In general, the smallest, oldest and slowest cards tend to work best with this library.
 
 Some people have trouble when SD cards have been formatted by Windows, but were able to solve the problem by formatting with [SD Card Formater](https://sd-card-formatter.en.uptodown.com/windows)
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