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Date:      Fri, 11 Sep 2015 15:48:21 +0200
From:      Patrick Hess <patrickhess@gmx.net>
To:        freebsd-questions@freebsd.org
Subject:   Re: USB physical ports
Message-ID:  <4365924.Nes7SDDcRu@desk8.phess.net>
In-Reply-To: <55F2C469.4030101@hiwaay.net>
References:  <55F1A507.70402@gmail.com> <55F2C335.3030304@gmail.com> <55F2C469.4030101@hiwaay.net>

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William A. Mahaffey III wrote:
> On 09/11/15 07:10, Ernie Luzar wrote:
> > But the real question is why is Freebsd USB rates capped at 20Mbps 
> > when the hardware says it's capable of 480Mbps?
> 
> I think you are confusing bits & bytes. 480 Mbps = 60 MBps, lower case 
> 'b' is bits, upper case 'B' is bytes, 8b / B (8b per B).

That's the first reason.

In addition, just because the bus is capable of transmitting up
to 480 Mb/s, that doesn't mean the devices connected to that bus
will also be able to process data at that rate. As a matter of fact,
most el-cheapo USB thumb drives won't. Try that again with a modern
HDD or even an SSD and you'll get much better results.

Patrick



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