Few weeks ago I started to use Arduino create web editor and love it. For me it is very convenient. However I found a huge performance difference in a firmware were I use the CAN library and serial monitor on a Arduino Micro. When I increase the amount CAN/serial message, read/interrupts, the application fails. Then I compiled on my local environment and all is ok. Then I found out that it is related to the AVR board version I use. The older ones are ok and the newest one fails. I tested several times and see again and again the same result. With winmerge I compared the 2 environments but there is no difference at all. The only difference I found, when selecting 2 different board versions are a few files in the windows prefetch folder. Does any have clue what could cause this. The online web create compiler has the same issue.