From owner-freebsd-questions@freebsd.org Fri Sep 11 13:48:32 2015 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 4CF1DA0072A for ; Fri, 11 Sep 2015 13:48:32 +0000 (UTC) (envelope-from patrickhess@gmx.net) Received: from mout.gmx.net (mout.gmx.net [212.227.17.22]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mout.gmx.net", Issuer "TeleSec ServerPass DE-1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id CF4FA10B9 for ; Fri, 11 Sep 2015 13:48:31 +0000 (UTC) (envelope-from patrickhess@gmx.net) Received: from desk8.phess.net ([24.134.52.245]) by mail.gmx.com (mrgmx102) with ESMTPSA (Nemesis) id 0M96Jd-1ZVCY608Cb-00CTi5 for ; Fri, 11 Sep 2015 15:48:23 +0200 From: Patrick Hess To: freebsd-questions@freebsd.org Subject: Re: USB physical ports Date: Fri, 11 Sep 2015 15:48:21 +0200 Message-ID: <4365924.Nes7SDDcRu@desk8.phess.net> User-Agent: KMail/4.14.3 (FreeBSD/10.1-RELEASE-p16; KDE/4.14.3; i386; ; ) In-Reply-To: <55F2C469.4030101@hiwaay.net> References: <55F1A507.70402@gmail.com> <55F2C335.3030304@gmail.com> <55F2C469.4030101@hiwaay.net> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:lIIxFCVa70LSvMPTT+s0ibwlTCHAR+JMonDUg/jFDn1LVBnznym h3MRND51VYqZ6CuL6ocUbDSsk/2IyqzfixRr38FXaVYI1Szfsub7QjuSWDNx35MKwQojLSL lUmZEdpn/qQSorP2zD3xW+tDuGOo9a5EtHMCgo0gnXKN9UdzP8wNbAwFUlfrlCDkKMhsoHZ NPgHD1c88wh8m3wMJvwmg== X-UI-Out-Filterresults: notjunk:1;V01:K0:rerEQO7a6mY=:XT7VfXADrjMAfG47qSKqeu WmQmJpIghzJpebyRMeuMyF+ERxNuMxEZbcdRliKjEyVF+REAu3nLG1VBvWDXhPLh7vn0vorMX PwJG4kRrqcWm9yfK8MxeLOoPiKINTcf2zzalIHBb36tWDkXZ1YAirFFxv7C/whtzrSBAcS1DH R8VNDz8K+m8fk76z9U6KQXIFlx81i2lrkyU/2jeyua8cBYMpHh0kgaMMqOoYSENv8rYYM4zpz B6cauaW/DBfKgNJ8mFxzLl1sSF9rwvzWrZHhZVy4GSro2lRmYwhKILzc7JY3wm4cXZVAwAb9+ dHJu4UjJCdZb1l91V3Xxqrw+ju7SiuKWpa4YjsvFPa732SevUByVEJ/bNHD5sdMyNUKjXA5xD fWtgkfNVumS4a5iZD+vpplRMkzj4Z196Jsg28gi2VHRqMnR5lT188Zniy3NLJboRLCk5r5AI+ b2dr/fwPkykq2WwuAQCHvK9oNjHxYbB3po/AL1ucgUNoY6U0cQt8TykpJ+ksU4dL6wUPe5cqo Z4T7HyarGgPApg28CyWT7MyvhTz6gbQb4Dr6pLT/aky8cR6SugWIirkB/2iUrYd8T/xHnPsn2 Ss1DqerW5EBIVFfl7d/Y1Wm69Py2VCgEs0ejksCKYUPMtEUmZsdJwry9lbkFy0W6gnRP6cP2S Kvcp6BK/eF1XxAU5MEVfWD+xGlsANz8umXOLCImeSkvGnk5iu36umzrmA+PrxAzx1Y1Nk13vi sg89999t8J2XAhUtaGY8K/j6Kvdrzi4l/dEW2w== X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 11 Sep 2015 13:48:32 -0000 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