Date: Mon, 23 Oct 2000 16:36:04 +0100 From: Steve Coles <scoles@tripos.com> To: freebsd-hardware@FreeBSD.ORG Subject: Promise Ultra-ATA100 vs FastTrak 100 Speeds Message-ID: <39F45AE4.ED8E4530@tripos.com>
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I have both of these Promise controllers. There has been a lot of press that these are the same cards, and I seem to remember that FreeBSD treats the FastTrak as just an IDE controller, so can anyone enlighten me on the vast speed differential between the two: Approx. Methodology ------------------- I attach 2 similar IBM 20Gb ATA 100 disks to each in turn, with appropriate cables, make a ccd stripe on the whole disk area and test the speed with dd at various block sizes / stripe sizes / FastTrak BIOS configuration. For all tests the transfer size was about 2Gb at the beggining of the disk, source / destinations = /dev/null or /dev/zero. Summarised Results ------------------ 1) One drive alone (no ccd) reads and writes at 30 Mb/Sec 2) Ultra 100 reads and writes at 29 MB/sec 3) FastTrak 100 writes at 50 MB/sec, reads at 48 MB/sec These results, within experimental error, are irrespective of: 1) Drive / IDE channel assigment - ie 2 cables Master+Master v. 1 cable Master+Slave 2) FastTrak BIOS configuration (FreeBSD just sees the plain drives) Questions --------- 1) Why is the Ultra so slow ( constructive answers only please :) ? 2) If I add another drive to the FastTrak will I see a similar (75% approx) performance increase ? 3) Does the FastTrak BIOS do anything ? Steve To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message
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