Both Mac and Windows are using the FTDI VCP virtual com port, (usb serial port emulation driver.) For the related setting on Windows see this post
FTDI defaults the "Latency Timer" on both Mac and Windows to 16 milliseconds. This causes large pauses to occur in the input stream from the OpenBCI data. The link above shows how to set the timer to 1 ms on Windows via a control panel setting. On Mac there is no equivalent control panel, but there is a file called Info.plist that can be copied into the Mac kernel extension driver folder, that will override the default. It turns out on Mac, setting that value to 1 ms has no effect (default continues). But setting it to 2 ms, does seem to do the override and buffering delays are improved substantially.
If you don't already have the FTDI driver installed, see this post
. Many pre-Mavericks Mac came with this preinstalled. If you have Mavericks or Yosemite you need to do some extra steps to disable the Apple driver, outlined in that link.
Make a backup copy of the old Info.plist in the folder below, and copy the new Info.plist over the old one:
Easiest thing to do at this point is to just reboot, which will pickup the new driver parameters. Using your Processing GUI, you should now see improved buffering performance. Our entry in the plist file is the one labeled:
"<key>FT X Series</key>"