From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stan Hoeppner Subject: Re: AMD 890GX vs 6Gbps SATA? Date: Tue, 16 Nov 2010 18:31:12 -0600 Message-ID: <4CE32250.8050401@hardwarefreak.com> References: <2DEEA3AB13739D45A22ADDB5086AEA0B915107@sshaexmb1.amd.com><1E8B869C0C6913418421A406C094DF7C82D812@sshaexmb1.amd.com><1E8B869C0C6913418421A406C094DF7C82D954@sshaexmb1.amd.com> <1E8B869C0C6913418421A406C094DF7C82DC6C@sshaexmb1.amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mo-65-41-216-221.sta.embarqhsd.net ([65.41.216.221]:49937 "EHLO greer.hardwarefreak.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755498Ab0KQAbO (ORCPT ); Tue, 16 Nov 2010 19:31:14 -0500 In-Reply-To: <1E8B869C0C6913418421A406C094DF7C82DC6C@sshaexmb1.amd.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: "Huang, Shane" Cc: James Cloos , linux-ide@vger.kernel.org, "Xu, Andiry" , "Petkov, Borislav" Huang, Shane put forth on 11/16/2010 4:04 AM: > Since your CAP.ISS is set to 0010(3Gbps), most likely you'll > have to ask your BIOS vendor to enable 6Gbps in one release. > Some BIOS vendors may set the max speed to Gen2 to save power. Unless you have a PMP on the other end of that SATA link with a bunch of striped drives, or an expensive SSD, you won't notice a performance difference between 3 Gb/s and 6 Gb/s link speed anyway: no single mech drive on the planet can come close to pushing 300 MB/s let alone 600. The fastest 15k SAS drives are peaking at around 200 MB/s IIRC. And there are few [affordable] SSDs that will saturate a SATA II link, let alone a SATA III link. My advice, FWIW, is to simply ignore this, unless you plan on attaching a device in the near future that can actually exceed 300 MB/s. Currently the only way to do this is with striped mech drives on a PMP, or with a $500+ SSD. -- Stan