Почему мой Intel SSD 520 так медленно?

Я запускаю новый установленный Ubuntu 12.04 LTS с ext4 на SSD 520 от Intel. Моя материнская плата - ASUS Crosshair (последний BIOS 1207) с контроллером SATA Sil 3132, который утверждает, что поддерживает SATAII. У меня включен TRIM. Но мои результаты довольно плохи по сравнению с тем, что можно было ожидать:

sudo hdparm -Tt /dev/sda

/dev/sda:
 Timing cached reads:   2510 MB in  2.00 seconds = 1255.51 MB/sec
 Timing buffered disk reads: 376 MB in  3.00 seconds = 125.21 MB/sec

Является ли моя системная плата узким местом? Ниже приведена информация о используемом SSD:

sudo hdparm -I /dev/sda
/dev/sda:

ATA device, with non-removable media
    Model Number:       INTEL SSDSC2CW120A3                   
    Serial Number:      CVCV227301JE120BGN  
    Firmware Revision:  400i    
    Transport:          Serial, ATA8-AST, SATA 1.0a, SATA II Extensions, SATA Rev 2.5, SATA Rev 2.6, SATA Rev 3.0
Standards:
    Used: unknown (minor revision code 0x0110) 
    Supported: 9 8 7 6 5 
    Likely used: 9
Configuration:
    Logical     max current
    cylinders   16383   16383
    heads       16  16
    sectors/track   63  63
    --
    CHS current addressable sectors:   16514064
    LBA    user addressable sectors:  234441648
    LBA48  user addressable sectors:  234441648
    Logical  Sector size:                   512 bytes
    Physical Sector size:                   512 bytes
    Logical Sector-0 offset:                  0 bytes
    device size with M = 1024*1024:      114473 MBytes
    device size with M = 1000*1000:      120034 MBytes (120 GB)
    cache/buffer size  = unknown
    Nominal Media Rotation Rate: Solid State Device
Capabilities:
    LBA, IORDY(can be disabled)
    Queue depth: 32
    Standby timer values: spec'd by Standard, no device specific minimum
    R/W multiple sector transfer: Max = 16  Current = 1
    Advanced power management level: 254
    DMA: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 udma5 *udma6 
         Cycle time: min=120ns recommended=120ns
    PIO: pio0 pio1 pio2 pio3 pio4 
         Cycle time: no flow control=120ns  IORDY flow control=120ns
Commands/features:
    Enabled Supported:
       *    SMART feature set
            Security Mode feature set
       *    Power Management feature set
       *    Write cache
            Look-ahead
       *    Host Protected Area feature set
       *    WRITE_BUFFER command
       *    READ_BUFFER command
       *    NOP cmd
       *    DOWNLOAD_MICROCODE
       *    Advanced Power Management feature set
            Power-Up In Standby feature set
       *    SET_FEATURES required to spinup after power up
       *    48-bit Address feature set
       *    Mandatory FLUSH_CACHE
       *    FLUSH_CACHE_EXT
       *    SMART error logging
       *    SMART self-test
       *    General Purpose Logging feature set
       *    WRITE_{DMA|MULTIPLE}_FUA_EXT
       *    64-bit World wide name
       *    IDLE_IMMEDIATE with UNLOAD
       *    WRITE_UNCORRECTABLE_EXT command
       *    {READ,WRITE}_DMA_EXT_GPL commands
       *    Segmented DOWNLOAD_MICROCODE
       *    Gen1 signaling speed (1.5Gb/s)
       *    Gen2 signaling speed (3.0Gb/s)
       *    Native Command Queueing (NCQ)
       *    Host-initiated interface power management
       *    Phy event counters
       *    unknown 76[14]
            DMA Setup Auto-Activate optimization
            Device-initiated interface power management
       *    Software settings preservation
       *    SMART Command Transport (SCT) feature set
       *    SCT Data Tables (AC5)
       *    Data Set Management TRIM supported (limit 1 block)
       *    Deterministic read data after TRIM
Security: 
    Master password revision code = 65534
        supported
    not enabled
    not locked
    not frozen
    not expired: security count
        supported: enhanced erase
    4min for SECURITY ERASE UNIT. 2min for ENHANCED SECURITY ERASE UNIT.
Logical Unit WWN Device Identifier: 5001517bb29a74d4
    NAA     : 5
    IEEE OUI    : 001517
    Unique ID   : bb29a74d4
Checksum: correct