I've been having the strangest thing happen with my arduino.
I have a sketch I am working on that controls a very long strip of RGB LEDS (150 LEDS).
I have debugged the code and it works perfectly fine, but every now and then when I make a change and use the serial monitor, my arduino UNO does what it should but at a highly reduced speed. I reset the board and nothing changed... I re uploaded the sketch... nothing changed...
I upload the previous version of the sketch...everything suddenly works fine...
At first I thought it was my sketch, but a side by side comparison shows no mistakes... I literally could just do something like add a comment and it will drop to quarter speed... I can delete the comment and the problem does not go away. Its the strangest thing... something is there but it is not visible. Eventually deleting even an empty line (carriage return) could fix the problem...
If this sounds like something you folks at arduino want to look into let me know and I'll e-mail you copies of the good and bad sketches when they happen.