Date: Sat, 21 Jul 2007 11:55:39 -0500 From: Dan Nelson <dnelson@allantgroup.com> To: Tim Daneliuk <tundra@tundraware.com> Cc: FreeBSD Mailing List <freebsd-questions@freebsd.org> Subject: Re: SATA 300 Drive Being Run At 150 Message-ID: <20070721165539.GA2579@dan.emsphone.com> In-Reply-To: <46A22253.8080100@tundraware.com> References: <46A22253.8080100@tundraware.com>
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In the last episode (Jul 21), Tim Daneliuk said: > I asked this question a while back, but needed to do more digging to make > sure I had latest sources etc. > > I have an Intel motherboard that shows this for a SATA controller: > > atapci1: <Intel ICH7 SATA300 controller> port 0x20c8-0x20cf,0x20ec-0x20ef,0x20c0-0x20c7,0x20e8-0x20eb,0x20a0-0x20af mem 0x90204000-0x902043ff irq 19 at device 31.2 on pci0 > > But the hard drive - a SATA 300 device - shows up like this: > > ad4: 238475MB <WDC WD2500JS-00NCB1 10.02E02> at ata2-master SATA150 > ^^^^^^^ > Using dd, I have confirmed that the drive is running nowhere near > SATA-III speeds, at least on reads: > > 968470075 bytes transferred in 7.132891 secs (135775249 bytes/sec) What was your dd commandline? If you've got more than 1GB of RAM and tested by reading a file and not the raw device itself, you just tested FreeBSD buffer cache. According to http://www.wdc.com/en/products/productspecs.asp?driveid=135 , that drive's maximum sustained speed is only 93.5 MB/sec, so it doesn't really matter if your interface is running at SATA150 or SATA300 unless you plan on reading exclusively from its 8MB buffer :) -- Dan Nelson dnelson@allantgroup.com
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