USB 1.0, which could handle a 12Mbps (megabits) maximum transfer speed, was released to the public in early 1996. It wasn't until 2000 that USB 2.0 was created with an increased transfer speed of 14Mpbs. FireWire technology was initially created in the mid-1980s by the Apple Computer company for high-speed data transfer within Macintosh hard drives. In 1995, the Electrical and Electronics Engineers (IEEE) organization released the first official Firewire specification and later in 1999, Apple began including Firewire ports in their G3 computers.
When taking audio information from a source such as a guitar or microphone to a computer, the rate, or speed, of data transfer is important when trying to reduce latency issues. While both USB and Firewire interfaces have relatively high data transfer speeds, Firewire is actually faster in sustained throughput (a term that means the average rate of successful message delivery). A common misconception is that since USB 2.0 is a 480 bps interface, it must surely be faster than the 400Mbps of a Firewire device. The truth is that the architecture difference of a Firewire device has a significant impact on its performance.
The main reason Firewire interfaces have a higher data transfer speed is due to its peer-to-peer architecture. This type of structure allows for intelligent peripherals to negotiate bus conflicts in order to decide which device is more suitable to oversee a data transfer. In other words, the computer is not forced to make those decisions so there is less system overhead. A USB device, however, uses a linear system known as a Master-Slave architecture. As its name implies, this structure forces the CPU, or Master, to dictate to the audio interface, or Slave, all arbitration functions to, from and between the attached peripherals. Consequently, this structure prevents higher speeds of data transfer since the additional computer functions directly delay the data transfer speed.
In order to test how well both a USB and Firewire audio interfaces perform with hard drives, read and write tests conducted by USB-ware.com have been conducted in which the same hard drive is connected to both devices while identical files are transferred, and the rate of data transfer is measured. The results have shown that in all instances, Firewire devices operate at higher speeds than USB. In a read test of 160 files (650MB total), Firewire was 70 percent faster than USB. In a write test of the same size of data, Firewire was 48 percent faster.
For many producers/recording engineers, a Firewire audio interface is preferred when working with an Apple computer. The reason to avoid a USB device is primarily the need to have the fastest data transfer rate as possible. Often engineers will record vocals, guitars and bass into Logic Pro or Pro Tools via an audio interface, and zero latency is a must. It can be extremely frustrating when trying to record a vocal line when the output is just a millisecond delayed. Also, most producers and engineers will base their decision on peer recommendations and customer reviews of various Firewire and USB interfaces. In conclusion, speed and sound quality normally are the most determining factors in deciding which device to purchase.