# Mac OS

## General discussion

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### Speed of FireWire

By ·
Apple advertises its FireWire speed at 400 Mbps. James McPherson's artice in the December 2000 issue of PC Troubleshooter, p15, says FireWire has a max bus speed of 50 Mbps. How does Apple arrive at the 400 Mbps figure? Thank you.

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### Speed of FireWire

by In reply to Speed of FireWire

The IEEE1394 standad specifies 400Mbps transfer rates or 50MB/s, I think it is the wording that got you confused on that one.
http://www6.tomshardware.com/consumer/00q3/000929/firewire-01.html#ieee_1394_background

http://www.zayante.com/p1394b/drafts/p1394b_rev100.pdf

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### Speed of FireWire

by In reply to Speed of FireWire

After I asked the question, I realized Mbps means millions of *bits* per second and MBps means millions of *bytes* per second. 8 bits = 1 byte, hence 400 Mbps = 50 MBps.

Thank you, deano511.

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### Speed of FireWire

by In reply to Speed of FireWire

The issue here is bits vs. bytes. Since a bit is only one eighth of a byte, 50 megaBYTES makes sense, since 50x8=400 MegaBITS. Same is true with your modem. 56k is 56kBITS, not bytes. Most things are rated in bits when speed is concerned. I think it's because companies want to make their technology look faster than it really is. Just my opinion.

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### Speed of FireWire

by In reply to Speed of FireWire

After I asked the question, I realized Mbps means millions of *bits* per second and MBps means millions of *bytes* per second. 8 bits = 1 byte, hence 400 Mbps = 50 MBps.

Thank you, cuziyq.

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### Speed of FireWire

by In reply to Speed of FireWire

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