From owner-freebsd-questions@FreeBSD.ORG Sat Nov 24 17:41:06 2012 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 9DC39572 for ; Sat, 24 Nov 2012 17:41:06 +0000 (UTC) (envelope-from lbc@bnrlabs.com) Received: from smtp3-g21.free.fr (smtp3-g21.free.fr [IPv6:2a01:e0c:1:1599::12]) by mx1.freebsd.org (Postfix) with ESMTP id 02FAA8FC08 for ; Sat, 24 Nov 2012 17:41:04 +0000 (UTC) Received: from mail.bnrlabs.com (unknown [82.224.61.5]) by smtp3-g21.free.fr (Postfix) with ESMTP id 18F5FA622F; Sat, 24 Nov 2012 18:40:58 +0100 (CET) Received: from [127.0.0.1] (unknown [172.20.96.112]) by mail.bnrlabs.com (Postfix) with ESMTP id 0A4A546072; Sat, 24 Nov 2012 18:40:57 +0100 (CET) Message-ID: <50B106AA.7060105@bnrlabs.com> Date: Sat, 24 Nov 2012 18:40:58 +0100 From: "Lucas B. Cohen" MIME-Version: 1.0 To: "Ronald F. Guilmette" Subject: Re: Compatability for various USB 3.0 / PCIe cards ? References: <21690.1353705073@tristatelogic.com> In-Reply-To: <21690.1353705073@tristatelogic.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: freebsd-questions@freebsd.org X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 24 Nov 2012 17:41:06 -0000 On 2012.11.23 22:11, Ronald F. Guilmette wrote: > > Well friends, it's that time of year again... yep, it's shop till you drop > time! For me it's usually *after* Christmas season, but whatever works :) > I can't imagine > that there is really that much different about the pricey ones to make > them worth the extra money.) I can imagine it. For a controller, negotiating USB 3.0 / XHCI protocol with a device is one thing, delivering the expected bandwidth is another. I've toyed around with enough cheap IDE and SATA adapters to know it takes more than a logo on the packaging to get decent throughput. Also, the bus needs to offer enough bandwidth to avoid being a bottleneck. Theoretical maximum speed for USB3 is 5 Gbits/s, that's a bit more than 2 PCIe lanes can sustain, so you'll want an adapter than plugs into a full-sized PCIe connector, unlike the Syba one. Hope this helps,