I am using an external USB drive for video. Is it possible to increase the speed of the drive to make rendering/copying/, etc., faster? When I have a couple of applications writing to the drive, and I open up the hard drive in the Finder, it takes awhile to load the files/folders.
There's not much you can do to "optimize" your transfer rate. OS X should be maxing out your USB connection as it is.
If that's not fast enough you might want to look at a USB 3 drive (if you're not already using one) or a Firewire drive which will give you better throughput. FireWire enclosures are a bit more expensive but they're worth it if you need higher throughput (for say, video rendering, etc).