Archived from groups: alt.sys.pc-clone.dell (
More info?)
User N wrote:
>
> "Nicholas Andrade" <sdnick484@nospam.yahoo.com> wrote in message
> news:jf18e.4656$dT4.4042@newssvr13.news.prodigy.com...
>
>> [] Bandwith wise, USB2 (480Mbps) & Firewire (400 or 800 Mbps)
>> are greater than a single drive, []
>
>
> Based on the benchmarks I've seen at Storage Review and elsewhere, I'm
> under the impression that many modern ATA drives can achieve sequential
> transfer rates of 50-60 MB/s on their outer tracks, and some SATA drives
> can achieve 60-70 MB/s. Furthermore, I'm under the impression that both
> burst at even higher rates [to and from their buffer]. What can USB 2.0
> Hi-Speed and Firewire 400 actually achieve?
>
> The 60MB/s and 50MB/s numbers sound good, but I don't recall ever
> seeing benchmarks that approached those rates. The external usb and
> firewire enclosure benchmarks I recall seeing reached the upper 30's
> (MB/s) for Firewire 400 and the lower 30's for USB 2.0 Hi-Speed.
> Which suggested to me that both interfaces would be a bottleneck.
>
> A quick Google...
>
http://www.extremetech.com/article2/0,1558,1150025,00.asp
>
http://www6.tomshardware.com/storage/20030411/wd_external_hd-09.html
>
http://www6.tomshardware.com/mobile/20041206/index.html
>
>
You know, I've never really looked into it, but you seem to be correct,
despite the high theoretical bandwith, the average bandwith is a bit
lower. In the first article, the drive was sustaining over 30MB/s in
USB2, which ought to be more than enough for most intents and purposes.
My main concern would be the CPU uitlization of external drives. They
don't support DMA, so the majority of the transfer overhead hits the
CPU. From what I just read, Firewire tends to use less CPU, and again,
if you just have one external drive this shouldn't be an issue.