FTDI has a detailed method for changing the latency setting that you can read here
While that method works, it is a little bit complicated and so we have simplified the process here. You should only use this method if you have NOT customized the FTDI driver previously. This method is based upon the Standard FTDI driver having been installed already on your system.
- 1. Backup the FTDIUSBSerialDriver.kext package from /System/Library/Extensions/
2. Delete the FTDIUSBSerialDriver.kext package from /System/Library/Extensions/ and then empty trash
3. Download and Save the modified FTDIUSBSerialDriver.kext to /System/Library/Extensions/
4. Paste the following command in a new Terminal Window and execute. You should be asked for your password
sudo chown root /System/Library/Extensions/FTDIUSBSerialDriver.kext
5. Using the Finder's "Get Info" option, Verify that the owner of /System/Library/Extensions/FTDIUSBSerialDriver.kext is now "system" with read & write privileges
6. Restart the Mac and verify that Serial ports are detected and working
If you run into difficulty, simply run the FTDI Installer again to restore the default Driver.