I think it's pretty much the more bits you send the more likely
one of them will be trashed, so smaller packets are a "bit" less
prone to corruption. If you have multiple senders they may interfere
with each other while competing for air-time.
You don't say what platform you are using. I've found
I am guessing here, but the first possibility that your serial port is not
fast enough to handle the amount of messages you are sending through it.
Therefore, as you increase the rate, new messages are in fact overwriting
the messages already 'in the pipe' (i.e. the serial port).
How are you writi
