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Velociraptor not faster than IDE Drive in my G4

1876 Views 42 Replies Latest reply: Mar 31, 2013 11:54 AM by Electricidad RSS Branched to a new discussion.
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lime-iMacG3 Level 1 Level 1 (15 points)
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Mar 16, 2013 4:47 PM

Hi,

 

I connected a WD Velociraptor 150GB HLFS via an SATA-IDE Adapter to the onboard controller of my PowerMac G4. I notice that opening folders takes about the same (felt) time as with the IDE drive.

 

I used a SATA-IDE adaptor for about 15-18,-EUR instead of a china thing from Ebay for 3-5,-EUR incl. shipping. It has a Jumper, too. But I guess it could still be the adapter, huh?

PowerMac, Mac OS X (10.4.11), PowerMac G4 AGP or Gigabit Ethernet
  • BDAqua Level 10 Level 10 (114,805 points)
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    Mar 16, 2013 5:42 PM (in response to lime-iMacG3)

    Hi, I think the limiting factor is your Bus speed, the weakest link in the chain so to speak.

  • japamac Level 7 Level 7 (24,390 points)
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    Mar 16, 2013 5:56 PM (in response to lime-iMacG3)

    The ATA/66 or ATA/100 bus is already moving data as fast as it can with an ATA/100 drive attached.

    A SATA to IDE adapted drive can only move data as fast as the bus can.

     

    So, a SATA to IDE adapted SATA 6.0 Gbps drive on an ATA/66 bus only gets about 50 MBps (an average max ATA/66 data rate of 66 MBps minus system overhead) or .4 Gbps (about .7 Gbps on ATA/100).

     

    If you want SATA 1.5 Gbps speed, get a PCI controller.

    Otherwise, all the adapter allows is the ability to use larger, more readily available drives; SATA drives.

  • japamac Level 7 Level 7 (24,390 points)
    Currently Being Moderated
    Mar 17, 2013 7:21 AM (in response to lime-iMacG3)

    I thought throughput (transfer rates of data) is different from acces time. I thought, if I have a faster rpm drive (or SSD) compared to a slower rpm drive, the accesss time gets faster (i.e. opening folders, applications will be visual more imediately).

    Access time would be seek time; movement of the head to the data location on the platter.

    All are fast, measurable but imperceptible.

     

    After that, the data must be read, moved to RAM or other cache, processed by the processor, returned to cache and used.

     

    In between, you have the ATA bus, PCI bus, USB bus or firewire bus. Then, there is the memory bus.

    All the data travels through all of this, with the weakest link being the slowest device/bus/process in the chain.

     

    Here are some tests that I did of the above 4 bus data rates:

    Hard Drive Benchmarks

     

    In the case of the GE G4, the ATA/66 bus is a choke point.

     

    SSD are the fastest (on a PCI controller) but may be considered wasted in a G4.

    My test results:

    SSD in a PPC Mac

     

     

    I have to say, when I copy like 500GB from one drive to another and count the time, I get about FW400 speeds

     

    As per the above explanation, there is more going on that a simple read.

     

    I never heard someone complain, but I have to be very carefull with the cables.

    The case interiors are very compact. Complaints are a mute point.

    Fill all 4 PC/AGPI slots, stuff in 4 drives and a fan or two and you have something that you don't want to open and close much.

     

     

    DSCN1923.jpg

  • Glen Doggett Level 4 Level 4 (1,780 points)
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    Mar 17, 2013 10:15 PM (in response to lime-iMacG3)

    lime-iMacG3 wrote:

     

    ...when I copy like 500GB from one drive to another and count the time, I get about FW400 speeds (I had between 35-38MB/s...

    are you copying from two drives on the same cable, or are the drives on separate channels on separate cables?

     

    I think if you are copying between Master/Slave drives on the same cable, the speed will not be as fast since read and write opeartions are sharing the channel.  And from one channel to another channel speed is limited to the slower channel speed.

  • OM617.952 Calculating status...
    Currently Being Moderated
    Mar 21, 2013 2:18 AM (in response to lime-iMacG3)

    The WD Velociraptor is as much an antique as your G4. Get a SSD instead.

  • OM617.952 Level 1 Level 1 (15 points)
    Currently Being Moderated
    Mar 22, 2013 5:27 AM (in response to lime-iMacG3)

    lime-iMacG3, you completely missed the point that the Velociraptor is junk.

     

    Its seek time is 4ms. Even the cheapest SSD today has a seek time of 0.1ms or less and will very easily saturate an ATA/100 bus. Thats 40x faster seek speed.

     

    Seek time is completly independent of the bus speed.

     

    Why are people always talking about boot time and the time Applications and folders take to open and that this would be faster with a Velociraptor or SSD?

    As said before, the Velociraptor is an obsolete antique. It was made for a time before SSD drives became consumer affordable. SSD drives are better in every way except for purchase price.

     

    What we think as faster access (seek) is actually the data transfer rate.

    Incorrect.

    Seek time is exactly what its called, time it takes to access two different files. It has nothing to do with transfer rate, its a mechanical limit of the drive. An SSD has no moving parts so there is no delay accessing them and file fragmentation has zero impact on drive performance.

     

    if I would try a SSD (not that I would even consider this)

    And that is why you're stuck in the past with slow antiques.

     

    <Edited By Host>

  • Electricidad Level 1 Level 1 (70 points)
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    Mar 23, 2013 6:20 PM (in response to lime-iMacG3)

    My assumption was not getting a new class lightning fast machine, but to see a visible difference in the pure action of a folder poping open.

    That is precicely why you should get an SSD.

  • Csound1 Level 7 Level 7 (32,395 points)
    Currently Being Moderated
    Mar 23, 2013 6:42 PM (in response to Electricidad)

    Which drive do you suggest, and what method would you choose to connect a Sata drive to the IDE bus in a G4?

  • Electricidad Level 1 Level 1 (70 points)
    Currently Being Moderated
    Mar 23, 2013 6:52 PM (in response to Csound1)

    Any of them. Since data rate is limited by the ATA100 bus, it doesn't matter which one you get as any of them will easily saturate the bus and respond as fast as the ATA controller can issue commands.

     

    You can either connect it exactly as the VR with an adaptor or you can get a bootable PCI SATA card to take advantage of the drive's speed.

     

    There is nothing special about how SSD drives work. They merely lack the pyscial heads and rotating media that restricts HD drive performance.

  • Csound1 Level 7 Level 7 (32,395 points)
    Currently Being Moderated
    Mar 23, 2013 6:56 PM (in response to Electricidad)

    Transfer rate from an avaerage SSD is 600Mb/s (approx), the internal bus will limit that to 66Mb/s and a pluging PCIe card to 124Mb/s. At that rate they will be no faster than an HDD. Why suggest the expense of an SSD when the performance will be better than an HDD (which will be much larger for the same price)

     

    Bad advice.

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