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  1. #1
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    Question Windows 7 SSD on RAID Controller

    I recently installed an SSD attached to a PERC RAID controller in my workstation.

    Due to the fact that the nature of the hardware is 'hidden' behind the RAID controller, windows 7 has no way to know that it is an SSD.
    So a couple questions:
    1. Does windows 7 treat SSDs differently than spinning drives?
    2. If so, how can I inform windows 7 that this is in fact an SSD and thereby maximize performance and longevity?

    BTW, the reason I am connecting it to the RAID controller is that it's faster than the onboard SATA controller. It support caching, etc.

  2. #2
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    Some things in your post confused me, but I'll have a go at answering.

    RAID in this context is essentially a technique for speeding up access to data on spinning disks (note the plural) by spreading the data so that some is accessed from one disk, some from another. The overall access time is reduced because the access requests are handled by multiple queues rather than a single queue.

    Obviously then (I hope it is obvious) for a single spinning disk RAID makes little difference to performance - maybe 10% at the very most - and it will typically make even less difference to a single SSD.

    You may of course have a RAID controller that is simply faster than your onboard SATA controller, but there again you could have another SATA controller that is also faster than the onboard installation.

    Longevity is maximised by spreading the writes as evenly as possible across an SSD. I am unsure how that would work with a RAID controller which is also implementing its own version of spreading the data around - unnecessarily, as described above. My suspicion is that any longevity management by Windows will fail as the controller will rule.

    SSD write speed is maximised by the TRIM function. For that to work, TRIM support is needed in each of Windows (ie Windows 7 and above), in your chosen disk controller and in your SSD's firmware.

    I am mystified by your reference to caching, as most SATA controllers support caching in one form or another. Or are you referring to the use of a small SSD to act as the cache for a larger HDD ? If this is the case, you would get improved performance at boot time and on first loading an application but, as soon as data is loaded into RAM, the SSD caching will make no difference.

    If you are looking for maximum overall system speed, eg for gaming, you might get better guidance at a dedicated gaming or hardware forum (such as Tom's Hardware) since much of what I have written about is happening outside Windows.

    PS You could of course implement RAID-0 across multiple SSDs but it is by no means certain that overall performance will increase - some operations will execute faster, others will slow down . . .
    Last edited by MartinM; 2016-07-29 at 14:46.

  3. #3
    Super Moderator jwitalka's Avatar
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    Actually,, RAID was developed as an error resiliency mechanism not a speed improvement. Data and error correction codes were spread among several disks such that data can be reconstructed in the event of any single disk failure. A side effect is that reads can be slightly faster but writes are slightly slower.

    Jerry

  4. #4
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    If you only have one SSD then you can not use RAID and the controller will not allow you to set up RAID. Windows will treat the SSD as an SSD.

    cheers, Paul

    p.s. I doubt your PERC controller will be faster than the onboard SATA controller in real life.

  5. #5
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    Jerry: there are several version of RAID - some just increase speed eg RAID-0 (and kiss goodbye to any hope of file recovery !), others increase resilience.

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