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Speed not right, SSD RAID 0

By cduma
Jul 11, 2010
  1. I am trying to use two 30GB 230MBps SSD's in RAID0 and after much difficulty with windows installation and other issues its now running but, I am only getting 122MBps read. I have all my drivers in order and I am using a quad core amd 2.8GHz cpu and the gigabyte 880ga-ud3h board. Any ideas?
     
  2. jobeard

    jobeard TS Ambassador Posts: 13,474   +329

    Owing to the bandwidth bottleneck of the bus they connect to, DRAM SSDs cannot read and write data as fast as main RAM can, but they are far faster than any mechanical hard drive. ​
    In other words, the DMA transfer rate of your system is the limiting factor for all devices attached.
     
  3. cduma

    cduma TS Rookie Topic Starter Posts: 20

    When I was using a single SSD I was getting data rates of 195MBps. Why would RAID0 be slower?

    And what do you mean DRAM? They are NAND
     
  4. jobeard

    jobeard TS Ambassador Posts: 13,474   +329

    single device vs raid-x has extra overhead to manage the extra device(s) so I would expect
    some loss.

    the ref to DRAM was a quote from a wiki; yes I saw you have NAND devices, but the overhead of raid-x and the limit of DMA transfer still apply
     
  5. cduma

    cduma TS Rookie Topic Starter Posts: 20

    Ah, so perhaps I should have done a little research before I went out and bought two SSD's then. This sucks.
     
  6. jobeard

    jobeard TS Ambassador Posts: 13,474   +329

    find a tool to test HD raw read write performance and try that on your Raid-0 :)
     
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