gecko said:
I bought two Seagate 'FreeAgent' external hard drives (500GB) at
separate times. I mistakenly bought two different models - one has
SATA and Firewire in addition to USB, but the other only has USB.
Seagate tells me that firewire is not faster than USB on desktop PCs,
but is faster on MACs.
That surprises me. Is it true?
-GECKO
Firewire comes in 1394a (400 megabits/sec) and 1394b (800 megabits/sec).
I suppose some might perceive that 1394b has more market penetration
on Macintosh systems, than on PCs, but I have seen the odd PC motherboard
that sported a 1394b port. You can also get add-in cards with 1394b.
SATA = 150MB/sec or 300MB/sec, and actual transfers would be platter limited
Firewire = 50MB/sec or 100MB/sec, and actual transfers will be less
USB2 = 60MB/sec theoretical, but practical rates are around 30MB/sec
for enclosures.
Some Firewire 800 benchmarks.
http://www.barefeats.com/note01.html
Various ports compared on Macs.
http://www.barefeats.com/hard70.html
1394a here, is able to do more than USB2.
http://www.tomshardware.com/de/Vergleich-Externe-Festplatten-eSATA,testberichte-239800-11.html
Where 1394a sometimes falls down, is when drives are daisy chained. (I
used to own two 1394a enclosures and noticed this in testing. There is
a difference between putting a chain of two drives, versus connecting
each drive directly to the computer. The packets are "store and forward",
through the chip inside the drive #1 enclosure.)
computer ----- drive #1 ------ drive #2 (drive #2 is slower, like 20MB/sec)
computer ----- drive #1 (a better config)
----- drive #2
HTH,
Paul
