Message-ID: <44EE6149.7000404@garzik.org>
Date: Thu, 24 Aug 2006 22:32:41 -0400
From: Jeff Garzik <jeff@garzik.org>
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To: Marc Perkel <marc@perkel.com>
CC: Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: SATA 150 vs SATA 300
References: <44EDBD0C.9040501@perkel.com>
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Marc Perkel wrote:
> Another speed related question. How much faster are SATA II drives 
> compared to regular SATA drives in real life? And - does NCQ really 
> help? I'm just looking for a general guess in the form of, "The Disk IO 
> upgrading to SATA II with NCQ will generally be X% faster." What value 
> is X?

SATA 150 and SATA 300 refers to interface speed (1.5Gbps or 3Gbps). 
Unless its entirely flash-based or RAM-based, it is highly unlikely that 
your disk max out the SATA cable bandwidth.

There is "SATA II is x times faster" rule, because it depends on the 
drive mechanics inside.  A SATA II drive may be exactly the same speed 
as SATA I, except that it is upgraded to support NCQ and other SATA II 
features.

NCQ definitely helps.

	Jeff


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