медленно работает raid 5

стоит RH7.1 scsi контроллер adaptec на рэйде скорость чтения записи ~13М\с хотя на этой же машине на такомже контроллере стоит ёще 1 винт , но на нём скорость ~70M\с может кто сталкивался с похожим ?


вот в дополнение
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ядро - 2.4.9-vmnix2
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03:04.0 SCSI storage controller: Adaptec AIC-7902 (rev 03)
Subsystem: Intel Corporation: Unknown device 3424
Flags: bus master, 66Mhz, medium devsel, latency 64, IRQ 30
I/O ports at 2800 [disabled] [size=256]
Memory at fe9d0000 (64-bit, non-prefetchable) [size=8K]
I/O ports at 2c00 [disabled] [size=256]
Expansion ROM at fe880000 [disabled] [size=512K]
Capabilities: [dc] Power Management version 1
Capabilities: [a0] Message Signalled Interrupts: 64bit+ Queue=0/1 Enable-
Capabilities: [94] PCI-X non-bridge device.

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cat /proc/scsi/aic79xx/1
Adaptec AIC79xx driver version: 1.3.7
Adaptec AIC7902 Ultra320 SCSI adapter
aic7902: Ultra320 Wide Channel B, SCSI Id=7, PCI 33 or 66Mhz, 512 SCBs
Allocated SCBs: 32, SG List Length: 85

Serial EEPROM:
0x17c8 0x17c8 0x17c8 0x17c8 0x17c8 0x17c8 0x17c8 0x17c8
0x17c8 0x17c8 0x17c8 0x17c8 0x17c8 0x17c8 0x17c8 0x17c8
0x9f4 0x146 0x2807 0x3010 0xffff 0xffff 0xffff 0xffff
0xffff 0xffff 0xffff 0xffff 0xffff 0xffff 0x430 0xe3f7

Target 0 Negotiation Settings
User: 320.000MB/s transfers (160.000MHz RDSTRM|DT|IU|QAS, 16bit)
Goal: 320.000MB/s transfers (160.000MHz RDSTRM|DT|IU|QAS, 16bit)
Curr: 320.000MB/s transfers (160.000MHz RDSTRM|DT|IU|QAS, 16bit)
Transmission Errors 0
Channel A Target 0 Lun 0 Settings
Commands Queued 885779
Commands Active 0
Command Openings 64
Max Tagged Openings 64
Device Queue Frozen Count 0
Target 1 Negotiation Settings
User: 320.000MB/s transfers (160.000MHz RDSTRM|DT|IU|QAS, 16bit)
Target 2 Negotiation Settings
User: 320.000MB/s transfers (160.000MHz RDSTRM|DT|IU|QAS, 16bit)
Target 3 Negotiation Settings
User: 320.000MB/s transfers (160.000MHz RDSTRM|DT|IU|QAS, 16bit)