USB 2.0 Transfer Issues with Vista & External Drive

[Fyvush Finkel]

I just purchased a Seagate FreeAgent external hard drive with USB 2.0. When
I hook it up to my system (nvidia 680sli motherboard) the transfer speed is
only 28.5-29 MBs. The documentation that comes with the external drive says
that USB 2.0 can transfer at a rate of 400 MBs.

Why the extreme discrepency between what is written on the docs and actual
use with Vista Ultimate? My machine has 4GB of RAM, a 2.4 GHz dual core
processor, so it is fast enuf. Anyone have an explanation?

Thanks

 

[Guest]

Remember that transfer rates depend on the entire path of transfer. Disk
access time, bus speeds etc. The intent of USB 2.0 is not to be the limiting
factor.

 

[Fyvush Finkel]

The motheboard has an 800MHz FSB. The SATA drives have at least a 100MBs
transfer rate and the bus is extremly fast. I can't believe they are
restricted to 29MBs when data from the SATA drives transfer across the same
bus at many times the speed of the USB device. What else could be the
problem?

 

[R. McCarty]

USB external drives will likely never exceed a sustained throughput
beyond 30.0 Megabytes per second. Note the 480 Mega is rated
in "Bits" not Bytes. For true external performance similar to internal
drives you'd need to use an External or eSATA drive. External USB
drives are convenient, but not known for their speed.

 

[Fyvush Finkel]

Thanks for the clarification. That makes more sense and I now I think I'll
return it for an eSATA drive. One question. How would I connect the eSATA
drive to the system?

 

[R. McCarty]

I use an AcomData kit. It comes with a PCI card, External drive
(WDC 250-Gigabyte) and a cable. Because it's served from the
PCI bus it's speed gets caped at around 65 Megabytes a second.
I bought my kit from CompUSA, but they've closed or are closing
a large number of their stores.
Here's a link to the manufacturer's product page:
http://www.acomdata.com/hdp/fs.html
There are all kinds of other solutions, Tiger Direct has an Outlet
store where I live and they sell SATA-II expansion cards and
enclosures that you can build your own kit. ( Picking the drive to
use with it.) Many new motherboards come with a eSATA socket
on the pack panel to use an external drive.