Lampduino - an 8x8 RGB Floor Lamp

Step 20 Reducing FTDI Serial Latency

If you use a FTDI-based serial port, including an Arduino Duemilanove, there is a 16ms latency introduced by the driver.  This short latency normally does not cause problems.  However, if you decide to implement the music synchronization feature described in a later step, any extra delay between the host and Colorduino communication will cause a lag between the music beats and the response on the display.  If you are running Microsoft Windows, you can tune down the latency via the FTDI driver's advanced settings.

Start the Windows Device Manager while your FTDI USB->Serial cable or Arduino Duemilanove is attached.

Look for its corresponding USB Serial Port under Ports (COM and LPT).

Right click on it, and select Properties from the popup menu.  Next, click the Port Settings tab, and click the Advanced... button.

In the dialog which pops up, change the Latency Timer (msec) value to 1, and click OK.

After you disconnect/reconnect your device, the new Latency Timer value will take effect.

I am not sure if there are similar settings in OSX or Linux.  Hopefully, someone can dig up a similar IOCTL to achieve the same effect.