FireWire 800, or IEEE 1394b, transfers data at up to 54 MB/s in conjunction with a external high-speed hard disk, which easily outperforms other alternatives we have tested in the past. Also, when operated as a network adaptor, 1394b offers a data transfer rate of up to 400 Mbps. For data transfer involving files of several hundred megaBytes each, 30 MB/s was a typical data rate achieved, which far surpasses that of 100 Mbit Ethernet (see Benchmarks).
Firewire is not ideally suited for network traffic. When used as a network interface, FireWire suffers from the fact that it has to be compatible with numerous applications as opposed to network traffic alone. In addition, IPv4 over 1394 might not be optimized for maximum performance. What is more, the Windows network implementation does not enjoy the best of reputations, with both Unix/Linux mostly offering higher net transfer rates.
As mentioned above, FireWire also presents security risks, while connecting two computers via FireWire offers transmission rates that are far superior to conventional Ethernet systems. Networks of three or more PCs will create more traffic and thus decrease a FireWire network's performance. So it is hard to say to what extent it makes sense and when you should go for an Ethernet solution.
Despite the drawbacks, hopefully 1394b controllers will soon find favor among motherboard manufacturers, since the high-speed interface offers added value. Also, users should be able to shoulder the higher cost of the motherboard.
Ultimately, FireWire devices also constitute a useful application for PCI Express, since with 250 MB/s per channel, this would allow a future FireWire adaptor to be connected without causing a bottleneck.