On Sun, Dec 08, 2002 at 06:04:11PM -0500, Neal wrote: > Could this be a hardware or connecting cable problem? The transfer > speeds you reported are far slower than what one might expect from a > UDMA66 hard drive. > > My desktop has a Western Digital UDMA66 drive and a VIA 82C686A > controller. hdparm reports: > > hdparm -tT /dev/hda2 > > /dev/hda2: > Timing buffer-cache reads: 128 MB in 1.15 seconds =111.30 MB/sec > Timing buffered disk reads: 64 MB in 2.64 seconds = 24.24 MB/sec > > It doesn't matter which partition is interrogated, the average reports > are all about the same 24MB/sec +/- a few hundred K.
Garrh. See nate's reply; he has suggested that it is due to my chipset. So I need a new controller. Garrh. On my chipset x!=686A. I've got an 82C596A and the other one has a big heatsink stuck to it. The BIOS knows I have an 80-conductor cable, and seems quite happy to set UDMA66 as far as I can tell. But I have always had to pass ide0=ata66 to the Linux kernel to stop it coming up as UDMA33. It would be interesting to measure the transfer speeds in DOS, but I don't have anything that'll handle that drive in DOS, much less produce results that can be related to hdparm (ie. no idea exactly what it's testing). For buffer-cache reads I get just under 50MHz, from any drive; the UDMA66, some SCSI-1 (10MHz) drives and even a slow old WDC2850. So I reckon this is measuring my system bus rather than the drives. Pigeon -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
