Hi re UDMA performance
Here is a quick test I did on an IBM 5400RPM drive connected to a Promise Technology, Inc. 20267 (rev 02) (ata66 or ata100 not sure). I think UDMA mode 2 is 33, but I could be completely wrong. It's interesting that mode 4 is faster than mode 5. I know this isn't very scientific, but it shows that even 5400 drives can benefit from ata66/100. linux# hdparm -X66 /dev/hde /dev/hde: setting xfermode to 66 (UltraDMA mode2) linux# hdparm -tT /dev/hde /dev/hde: Timing buffer-cache reads: 128 MB in 1.08 seconds =118.52 MB/sec Timing buffered disk reads: 64 MB in 3.15 seconds = 20.32 MB/sec linux# hdparm -X67 /dev/hde /dev/hde: setting xfermode to 67 (UltraDMA mode3) linux# hdparm -tT /dev/hde /dev/hde: Timing buffer-cache reads: 128 MB in 1.08 seconds =118.52 MB/sec Timing buffered disk reads: 64 MB in 2.60 seconds = 24.62 MB/sec linux# hdparm -X68 /dev/hde /dev/hde: setting xfermode to 68 (UltraDMA mode4) linux# hdparm -tT /dev/hde /dev/hde: Timing buffer-cache reads: 128 MB in 1.08 seconds =118.52 MB/sec Timing buffered disk reads: 64 MB in 2.18 seconds = 29.36 MB/sec linux# hdparm -X69 /dev/hde /dev/hde: setting xfermode to 69 (UltraDMA mode5) linux# hdparm -tT /dev/hde /dev/hde: Timing buffer-cache reads: 128 MB in 1.09 seconds =117.43 MB/sec Timing buffered disk reads: 64 MB in 2.33 seconds = 27.47 MB/sec linux# On another machine: A 7200 RPM drive connected to a via ata33 controler: /dev/hdc: Timing buffer-cache reads: 128 MB in 0.79 seconds =162.03 MB/sec Timing buffered disk reads: 64 MB in 1.78 seconds = 35.96 MB/sec Looks like I should move this drive to a faster controler. Regards -- Rob Murray
