• Uno with a 250K baud bootloader
Is this a optiboot that is not currently supplied with the Arduino IDE?
Yes. It is not
supplied with the Arduino IDE. The one that comes with the IDE is configured for 115200 baud.
Is there a link the code for this?
Unfortunately, no. I don't think I even kept a copy of it. I built it solely to answer two questions, "Does baud rate make a significant difference?" and "Is 250000 baud reliable?"
The answer to the second question is "yes", 250K baud is
reliable. I suspect 500K is also reliable but I have not performed any testing.
The answer to the first question...
Arduino 1.0.1-rc2, Avrdude 5.11
#1: Uno, Optiboot 3.3, 115200 baud: 2821.8
#2: m328p on a breadboard w/ Pololu as converter, Optiboot 4.4, 115200 baud: 3403.1
#3: m328p on a breadboard w/ Pololu as converter, Optiboot 4.4, 250000 baud: 5313.9
The serial converter makes a difference (#1 versus #2). The Pololu appears to be a more efficient converter.
The baud rate makes a big difference (especially on the verify pass) (#2 versus #3).
By the way Coded Badly, thanks for the break down of programmer speeds!
You are welcome. If I ever have time, I'll write-up the details (and try to remember to post a link here).