"Kath" said:
Hey All...
Is anyone having problems with their USB transfer rates to external HDDs? I
have an ASUS A7N8X-Deluxe and A7N8X-E Deluxe and am trying to connect and
transfer with a variety of external HDDs in different enclosures. I am
transferring 10GB to 12GB files between my internal drives and the USB
drives, but each file is taking an unreal amount of time to be written to
the drive. Forget trying to do video editing on the externals...
Just wondering if anyone is seeing this, or can hep me get better transfer
rates.
Thanks!
Scott
Performance might be limited by the bridge between USB and IDE inside
the enclosure.
Try searching for "External SATA" in your favorite search engine.
SATA offers 150MB/sec maximum cable transfer rate, and with its
low voltage differential interface, shouldn't have emission characteristics
much worse than USB 2.0. With decently designed cables (good shielding),
your external drives could be SATA, instead of USB or Firewire.
(Note - avoid the hyperbole in some of the review articles - SATA
cable rate is limited to 150MB/sec, due to the 8B/10B data encoding on
the cable, and the PCI bus the controller card plugs into is limited to
practically ~100MB/sec. Since most drives sustained internal data
transfer rate is sub 100MB/sec, there is still an advantage to doing
some kind of RAID with the SATA drives. Better yet, use a "server"
motherboard with 64bit or 66MHz PCI slots, as then you can cram more
transfer bandwidth into your computer.)
I would hope there are products that offer more than one SATA
interface per card like this one does:
http://www.3dvelocity.com/reviews/rocket_mate/esata.htm
Firewire 800 is another alternative. Currently, Firewire 800 is more popular
on the Macintosh side, as Apple Computer puts Firewire 800 on some of
their newest computers. I think Firewire 800 cards are also available
for PCs. While Firewire 400 bridge boards (the board inside the enclosure)
were limited to maybe 22-30MB per second, the Firewire 800 bridge boards
seem to be doing a little better. I think some of the USB 2.0
bridges have similar limitations to the same generation of
Firewire 400 bridges. (Also note, if you daisy chain Firewire
external enclosures, the drive on the end of the cable gets a lower
transfer rate than the one that connects first to the computer, again
due to "thru-transfer" limits of the bridge board(s) in the path.)
But, for all out performance, try to put SATA into your equation.
Consult the performance database at:
http://storagereview.com/comparison.html
for the best disk to use in an external enclosure. The WD Raptors
offer somewhere around 70MB/sec internal transfer rate at the beginning
of the disk, and two of those RAIDed should do a good job of
saturating your ~100MB/sec PCI bus.
All you need for a fast transfer rate, is money
))
Have fun,
Paul
