testing disk "speed" with hdparm -t

[Joachim Backes]

Hi,

I'm running F11. My box has 2 identical IDE disks (123 GB ATA Maxtor 
6Y120L0), /dev/sda and /dev/sdb. F11 is installed on /dev/sdb7.

-----------------------------------------------------------------------

hdparm -i /dev/sda /dev/sdb

/dev/sda:

  Model=Maxtor 6Y120L0                          , FwRev=YAR41BW0, 
SerialNo=Y3M40RDE
  Config={ Fixed }
  RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=57
  BuffType=DualPortCache, BuffSize=2048kB, MaxMultSect=16, MultSect=?16?
  CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=240121728
  IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
  PIO modes:  pio0 pio1 pio2 pio3 pio4
  DMA modes:  mdma0 mdma1 mdma2
  UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6
  AdvancedPM=yes: disabled (255) WriteCache=enabled
  Drive conforms to: ATA/ATAPI-7 T13 1532D revision 0: 
ATA/ATAPI-1,2,3,4,5,6,7

  * signifies the current active mode


/dev/sdb:

  Model=Maxtor 6Y120L0                          , FwRev=YAR41BW0, 
SerialNo=Y3M40RLE
  Config={ Fixed }
  RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=57
  BuffType=DualPortCache, BuffSize=2048kB, MaxMultSect=16, MultSect=?16?
  CurCHS=4047/16/255, CurSects=16511760, LBA=yes, LBAsects=240121728
  IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
  PIO modes:  pio0 pio1 pio2 pio3 pio4
  DMA modes:  mdma0 mdma1 mdma2
  UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6
  AdvancedPM=yes: disabled (255) WriteCache=enabled
  Drive conforms to: ATA/ATAPI-7 T13 1532D revision 0: 
ATA/ATAPI-1,2,3,4,5,6,7

  * signifies the current active mode

-------------------------------------------------------------------------

Testing the speed of /dev/sdb with "hdparm -t /dev/sdb" shows constantly 
56 MB/s:


/dev/sdb:
  Timing buffered disk reads:  170 MB in  3.01 seconds =  56.56 MB/sec

/dev/sdb:
  Timing buffered disk reads:  170 MB in  3.01 seconds =  56.43 MB/sec

/dev/sdb:
  Timing buffered disk reads:  168 MB in  3.00 seconds =  55.97 MB/sec

/dev/sdb:
  Timing buffered disk reads:  170 MB in  3.01 seconds =  56.42 MB/sec

/dev/sdb:
  Timing buffered disk reads:  168 MB in  3.03 seconds =  55.49 MB/sec

------------------------------------------------------------------------
But testing /dev/sda with "hdparm -t /dev/sda" shows extremly variable 
values:

/dev/sda:
  Timing buffered disk reads:   32 MB in  3.02 seconds =  10.60 MB/sec

/dev/sda:
  Timing buffered disk reads:   24 MB in  3.01 seconds =   7.97 MB/sec

/dev/sda:
  Timing buffered disk reads:   36 MB in  4.01 seconds =   8.97 MB/sec

/dev/sda:
  Timing buffered disk reads:   76 MB in  3.05 seconds =  24.91 MB/sec

/dev/sda:
  Timing buffered disk reads:   46 MB in  3.06 seconds =  15.03 MB/sec
----------------------------------------------------------------------
Board: MSI K7N2 Delta

lspci

00:00.0 Host bridge: nVidia Corporation nForce2 IGP2 (rev c1)
00:00.1 RAM memory: nVidia Corporation nForce2 Memory Controller 1 (rev c1)
00:00.2 RAM memory: nVidia Corporation nForce2 Memory Controller 4 (rev c1)
00:00.3 RAM memory: nVidia Corporation nForce2 Memory Controller 3 (rev c1)
00:00.4 RAM memory: nVidia Corporation nForce2 Memory Controller 2 (rev c1)
00:00.5 RAM memory: nVidia Corporation nForce2 Memory Controller 5 (rev c1)
00:01.0 ISA bridge: nVidia Corporation nForce2 ISA Bridge (rev a4)
00:01.1 SMBus: nVidia Corporation nForce2 SMBus (MCP) (rev a2)
00:02.0 USB Controller: nVidia Corporation nForce2 USB Controller (rev a4)
00:02.1 USB Controller: nVidia Corporation nForce2 USB Controller (rev a4)
00:02.2 USB Controller: nVidia Corporation nForce2 USB Controller (rev a4)
00:04.0 Ethernet controller: nVidia Corporation nForce2 Ethernet 
Controller (rev a1)
00:06.0 Multimedia audio controller: nVidia Corporation nForce2 AC97 
Audio Controler (MCP) (rev a1)
00:08.0 PCI bridge: nVidia Corporation nForce2 External PCI Bridge (rev a3)
00:09.0 IDE interface: nVidia Corporation nForce2 IDE (rev a2)
00:1e.0 PCI bridge: nVidia Corporation nForce2 AGP (rev c1)
02:00.0 VGA compatible controller: nVidia Corporation NV34 [GeForce FX 
5200] (rev a1)
-----------------------------------------------------------------------

Does somebody have an explanation for this?

Any help is welcome.

Regards

Joachim Backes <joachim.backes at rhrk.uni-kl.de>

http://www.rhrk.uni-kl.de/~backes

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