Firewire: 1394a vs 1394b port

[Deep23]

I recently came to know about a new thing about firewire. Honestly speaking I was not aware of the fact that there is a 1394 a- and b-variant of it. "B" variant provides up to 800MB/s while the "A" variant gives max 400MB/s. How do I find out what version I have on my motherboard?

[samar69]

They differ in there looks completely. Look at the attachments. The top is FW400 (1394a), while the bottom is FW800 (1394b).

[Howitzer]

Look at my attachments. A- variant is on the right side, while B-variant is on the left side.

[Deep23]

Ok thanks.

Another question: is it true that 1394a Firewire will work faster than USB 2.0? I read that even though USB 2.0 will provide up to 480MB/s, it is likely not to more than around 280MB/s?

[samar69]

Yes it is actually correct that FireWire is faster than USB 2.0. The throughput may lead you to believe that USB 2.0 provides better performance. But the differences in the architecture of the two interfaces have a huge impact on the actual sustained "real world" throughput. FireWire uses a "Peer-to-Peer" architecture in which the peripherals are intelligent and can negotiate bus conflicts to determine which device can best control a data transfer. On the contrary, USB 2.0 uses a "Master-Slave" architecture in which the computer handles all arbitration functions and dictates the data flow to, from and between the attached peripherals. This certainly adds additional system overhead and results in slow performance and less-efficient data flow control.