Some FireWire cables can cause issues due to lack of shielding and gauge of wire, etc. Also connecting multiple devices to the same FireWire port can be an issue in some cases with some computers. And there is a difference in FireWire ports to contend with and the same is true with various bridge technology used in making the EIDE to FireWire bridges. All modern ATA and FireWire drives do multiple times that rate. But remember the rate is one thing and having a clean stream of data is annother.
Clean stream is as important as sustained data rate.
For example some bridge construction is not properly engineered which causes bus resets to occur which interrupts data causing dropped frames. And in this case the drive would test for 18 to 19 MB sec but due to resets the drive could not fill the buffer due the interruption thus dropped frames take place. I have 2, running great. I am looking for a good mailorder source for an Abit Vp6 motherboard. I'm looking for someone I can talk with about it.