Date: Sun, 22 Jul 2012 17:45:00 -0500 From: Adam Vande More <amvandemore@gmail.com> To: Jakub Lach <jakub_lach@mailplus.pl> Cc: freebsd-questions@freebsd.org Subject: Re: "da0: 40.000MB/s transfers" What was rationale behind pegging USB 2.0 at 40MB/s? Message-ID: <CA%2BtpaK3qWnh_MUfBAEzTexsJdXu4JP5nPG=z4jJdUUd2qwSUxQ@mail.gmail.com> In-Reply-To: <1342992043358-5729028.post@n5.nabble.com> References: <1342992043358-5729028.post@n5.nabble.com>
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On Sun, Jul 22, 2012 at 4:20 PM, Jakub Lach <jakub_lach@mailplus.pl> wrote: > Hi, > > I was fortunate enough to buy USB 3.0 pendrive, > which actually works with FreeBSD just ripped from > package! (normal _empty_ FAT filesystem, no > garbageware added, no need to format). > > It actually bounces from 40MB/s limit when reading > from it. > > Writing is about 18MB/s. > > Device is supposed to be "467x" which should > be about 70MB/s. > > And USB 2.0 hard limit is 60MB/s. > > Wouldn't be nice to squeeze few additional > MB/s? > You are suffering a misunderstanding of how USB 2 works. There is a lot of overhead to it. If you want USB 3 speeds, buy a USB 3 controller. -- Adam Vande More
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