How do I tell Firewire 400 vs 800 ports

Question

The manual just says "if you have". The two firewire ports on the back look the same. I have the white 20" iMac, about a year old or so.
I'm looking to get an external hard drive for backups, and I assume Firewire 80 is the way to go.

Answer 1

J D McIninch wrote:
That said, it hardly matters. If you're only using one disk at a time, it is not likely to matter. The theoretical maximum transfer rate for a 7200 RPM disk is something like 55 MB/sec, but in practice you rarely see more than half that.
I'm not aware of any "theoretical maximum" transfer rate, but in any case,
55 MB/s is SLOOOOOW by today's standards. Many ordinary, garden-variety,
7200 rpm SATA drives routinely deliver anywhere from 80 to 120 MByte/sec
sustained R/W transfer rates -- and according Seagate technical forecasts,
the present technology (perpendicular recording / GMR heads) is nowhere
near its limit. Speed/density will continue to grow by leaps and bounds.
[Actual performance measurements for Real™ disk drives|http://www.tomshardware.com/charts/3-5-hard-drive-charts/maximum-read-tr ansfer-rate,666.html?p=1826%2C1782%2C1844%2C1772%2C1845%2C1780%2C1799%2C1777%2C1 803%2C1798%2C1788%2C1815%2C1812%2C1794%2C1805%2C1791%2C1809%2C1833%2C1807%2C1766 %2C1842]
Looby