HDD bus question (PM G5)

Discussion in 'PowerPC Macs' started by disconap, Jul 22, 2009.

  1. disconap macrumors 68000

    disconap

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    #1
    So I have a G5 tower with SATAI 1.5gb/s onboard. I ALSO have a PCI-X SATAII 3gb/s card. I'm reconfiguring and setting up OSX software RAID0, possibly multiples, but in trying to figure out where to set the OS, where to set scratch disks, etc., does anyone know in PRACTICAL terms if SATA2 over PCI-X would be faster than SATA1 onboard? All drives are SATA2 so there's no bottlenecks on the drive hardware end.

    Just curious, I'm trying to get the most out of a system that is FINALLY starting to show its age.
     
  2. 300D macrumors 65816

    300D

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    #2
    Except for actual drive throughput.
     
  3. disconap thread starter macrumors 68000

    disconap

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    #3
    Which is not a result of the drives, hence "there's no bottlenecks on the drive hardware end"...
     
  4. 300D macrumors 65816

    300D

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    #4
    Yes it is actually. Its the fault of the drive not being able to move data on/off platters quick enough.
     
  5. DoFoT9 macrumors P6

    DoFoT9

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    #5
    yes but aside from the obvious.. is the SataII PCI card going to perform worse then the normal 'interface'.

    what is the speed of the PCI connector??
     
  6. disconap thread starter macrumors 68000

    disconap

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    #6
    No, what I am saying is that it's not relevant to the question. It's sort of like asking which car is faster and pointing out that the automatic transmissions prevent either from being optimal. Sure, it's true, but it has nothing to do with that was asked.
     
  7. disconap thread starter macrumors 68000

    disconap

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    #7
    It's a 133mHz 64-bit PCI-X slot.
     
  8. DoFoT9 macrumors P6

    DoFoT9

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    #8
    to be honest i dont think that it will be fast enough for SataII speeds... ill do a bit of researching and check out the max speed.

    "The PCI-X spec specifies a bus design that can increases data throughput to a maximum of 1056 Mbytes/sec (over 1 Gbyte/sec)."

    from here.. not really proof but its sort of an indicator.
     
  9. disconap thread starter macrumors 68000

    disconap

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    #9
    I figured, but it's less about maximizing SATA2 (most newer machines and drives don't come close to doing that) and more about whether or not it's faster than the onboard SATA1 bus in actual terms. I.e., simply would one be faster than the other, would they be relatively equal, would one be more stable than the other in a RAID0 (I have two slots in both, so it wouldn't be mixed), that sort of thing.

    I mean if I saw actual 1gb/sec throughput on a G5 dual 2.0ghz box I'd be pretty shocked.
     
  10. DoFoT9 macrumors P6

    DoFoT9

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    #10
    ok right sure i see your angle now.

    this intel page says that the throughput of PCI-X 166MHz bus allows 1GB/sec. so 125MB/sec transfer rate. SataI being 1.5GB/sec is faster (187.5MB/sec), but not my much..

    as for stability and whatnot, the only way to tell is to try both!

    edit:: that page uses GB/sec, im not sure if it refers to bit/byte, if its refering to byte then the PCI way might be faster!!!

    interseting:: (from wiki)
     
  11. disconap thread starter macrumors 68000

    disconap

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    #11
    Just to update--I am currently running with my primary system being on a RAID0 on 2X500gb drives with 16mb cache on the system (1.5gb/s) and my primary scratch/active file RAID0 now being 2X160gb drives on the SATAII pci-x bus. I can't speak to technical specifics, but it's definitely breathed new life into my G5, I think it'll easily give me another year or two before I have to switch to Intel. :)
     

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