Intel RAID 5 configuration (slow write speed)


Been trying to configure a RAID 5 on a Intel server board. Read speed is excellent but the write
speed stays between 2 and 10mb/sec.

Read a lot on this forum; although a lot of good pointer, can't find what is wrong.
Here is the config:

OS name: Windows XP
OS Version: 5.1
OS Architechture: x86
Driver Name: LSI MegaSR RAID5
Driver Version: 13.21.0614.2010
Intel Board S5000XVN with RAID 5 key

5 Western Digital 2TB green
Strip size 64k
created 4 virtual drives of 1.818TB with default allocation unit size

Disk cache policy: Enable
Read policy: Always Read Ahead
Write Policy : Write Back

Any help to optimize those would be greatly appreciated.

10 answers Last reply
More about intel raid configuration slow write speed
  1. Is there a chance any of your disks are bad? I don't mean broken, just strangely slow. ~5MB/s is REALLY slow. What program are you reading that with? What is the LSI MegaSR RAID5? Is that completely different from Intel ICH10R? That's what I run my RAID 5 on.
  2. All disks are new and i've tested them individualy. I've used HD Tune Pro for the test which from
    what i've read in this forum is not perfect for RAID but real time transfert made by ViceVersa does confirm
    a write speed of 3mb/sec average .

    When using the system disk, which is Western Digital 1tb on sata port also, i get ~40mb/sec.

    The raid controller is actually Intel Embedded Server RAID Technology II using LSI driver.

    Does having the allocation unit size when formatting different then the stripe size have an impact on the
    write speed?
    I'm about to start burning incense as a last resort!
  3. Take a look at MB BIOS the Raid5 driver.
    1 - in the BIOS make sure SATAII mode is used
    2 - Down load the latest raid driver from Intel

    It should improved the speed, but it won't get to 210MB/sec

    Unless you used hardware raid controller like SPM393, Adaptec, HPT
  4. I've checked the Bios options but could't find anything ralated to SATAII mmode.
    The raid driver wasn't up-to-date but even with the new version i've installed, i still have
    a average write speed of 5MB/sec.
    If i could only get a 100MB/s, it would be perfect.


    "Unless you used hardware raid controller like SPM393, Adaptec, HPT"

    I thought that since it's onboard RAID it was consider hardware raid.

    Question: For RAID 5, should Tagged Queuing and Synchronous transfers be disable?
  5. Still researching a solution. Disabling Tagged Queuing and Synchronous transfers didn't make any difference.
    I am running out of options. There's got to be someone who created a Raid 5 on an Intel board with Windows XP?

    A lot of peoples in this forum points out Write Caching, which in On in the Bios (and Raid console). Is there any options
    in Windows Xp that would disable this (the option is grey out in the Device Manager)?

    Thanks for any help.
  6. I have not seen any Built-in Mobo RAID, that is hardware raid - Correct me if i'm wrong

    With SATAII connection:
    - Tagged Queuing and Synchronous and NCQ does offer advantage

  7. 2nd though.

    I think the slowness has to do with your virtual drives drives

    Why do you do this... for testing purspose.

    Just create a 2TB raid - forget about the remain capacity and see would that be faster

  8. Have you been able to resolve the slowness of your RAID?
    I have similar problem - using three WD Green 2TB on Intel RAID controller built-in on my Asus mo-bo. Write speeds are around 5MB/s. Just painful!
  9. Hi dmbruk,

    is a round up of what happen after.

    I finally manage to have a good write speed with this configuration using Windows 7 64bit (was on XP initially).
    Prolly the fact that the raid wasn't partition anymore (maybe?). But was working fine with good write speed.

    That being said, 2 month after i had already a western digital failing. Rebuild did work, so no lost of data
    but i didn't trust those drives anymore.

    Ended up buying a Adaptec Raid Controller ASR-5805 with Seagate Baracuda XT drives. Excellent write/read speed
    and no problem ever since.


    dmbruk said:
    Have you been able to resolve the slowness of your RAID?
    I have similar problem - using three WD Green 2TB on Intel RAID controller built-in on my Asus mo-bo. Write speeds are around 5MB/s. Just painful!
  10. I don't get it!
    you guy spend 100's or 1000's dollar for CPU, MB, Mem, .... even SSD to speed up, improved performance... but too cheap to spend $100.00 for an excellent hardware raid SPM393/SPM394...or any other hardware raid controllers.

    Go figure!
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