U160 works at 40?!?!

[Sirber]

Card:
Adaptec AIC7xxx driver version: 6.2.36
Adaptec 29160 Ultra160 SCSI adapter
aic7892: Ultra160 Wide Channel A, SCSI Id=15, 32/253 SCBs
Allocated SCBs: 36, SG List Length: 128

Cable:
U320 with terminator

HDD:
Seagate LVD U160 17GB

Speed:
User: 160.000MB/s transfers (80.000MHz DT, offset 127, 16bit)
Goal: 40.000MB/s transfers (20.000MHz, offset 63, 16bit)
Curr: 40.000MB/s transfers (20.000MHz, offset 63, 16bit)

Bench:
/dev/sda:
Timing cached reads: 496 MB in 2.01 seconds = 246.31 MB/sec
Timing buffered disk reads: 70 MB in 3.05 seconds = 22.93 MB/sec

Any idea why? :confused:

[Sirber]

HDD infos:

http://www.seagate.com/cda/products/discsales/marketing/detail/0,1081,344,00.html

sirber@detrinux sirber $ cat /proc/scsi/scsi
Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
Vendor: SEAGATE Model: ST318406LW Rev: 0109
Type: Direct-Access ANSI SCSI revision: 03

[Sirber]

I read something:These cards will operate in most motherboards with 32-bit PCI slots. The expansion slot must be compliant with PCI Rev. 2.1 or higher and must support Bus Mastering, however, in order for these SCSI cards to function properly. Please check with the motherboard manufacturer to see if the PCI Slots are fully PCI 2.1 compliant.

[Sirber]

Target 0 Negotiation Settings
User: 160.000MB/s transfers (80.000MHz DT, offset 127, 16bit)
Goal: 160.000MB/s transfers (80.000MHz DT, offset 63, 16bit)
Curr: 160.000MB/s transfers (80.000MHz DT, offset 63, 16bit)
Channel A Target 0 Lun 0 Settings
Commands Queued 5514
Commands Active 0
Command Openings 32
Max Tagged Openings 32
Device Queue Frozen Count 0

My HDD had a jumper to force SE mode :(

[dragongodz]

hahaha i see you have been having fun. :D

[Sirber]

:angry:

I lost 4 hours on that. Thorical speed got from 40MB/s to 160MB/s, but real speed got from 20MB/s to 29MB/s :(