Slow Hard Drive transfer speeds

Discussion in 'General Mac Discussion' started by ChrisFromCanada, Jul 22, 2004.

  1. ChrisFromCanada macrumors 65816


    May 3, 2004
    Hamilton, Ontario (CANADA)
    So I recently got a 200GB HD and hooked it up and it went fine but the transfers thus far have been VERY slow (20MB - 30MB/sec) and I think it is because it is splitting the speed on my ata-66 bus with my other HD so I think it would be a good idea to get a PCI ata-133 controller card but I am wondering if I need a special mac one or if this one will work. Any recomendations? Maybe 20MB - 30MB/sec is a good speed but seem to remember getting more before. Anyway I am getting a G5 in about a month so maybe I should live with the slow transfer until then. Also I know the G5's use SATA so is there any way I can get an ATA-133 to SATA adapter or should I just put this HD in a FW case?

    Thanks lots,
  2. iNetwork macrumors member

    Jul 20, 2004
    New Mexico
    20-30 Megs a second on a master/slave pata setup is actually pretty good. Remember that the pata cable can handle 66 megs/second total--it's shared bandwidth!!! With any consumer hard drives it is always best to have them each on their own channels; only using the master portion of the cable and configuring drives accordingly. Honestly, I'd wait until your new G5 came in and then put the hdd in a firewire 800 enclosure.

    It's also important to remember that the physical maximum transfer rate of the hard drive is different than that of the interface. The newest hard drives now are just barely able to utilize all of the bandwidth that an ata66 cable can provide for it! It irritates me when someone thinks their hard drive can do 133 megs/second because the interface can. The physical read/write of the drive is the limiting factor, NOT the interface. Most mainstream hard drives sustain only 30-35 megs/second anyways. Note that many start at 60 megs a second but as the move towards the end of the disk, the fastest drives peak at a mere 34.x megs/second.

    I also forgot to mention that write speeds are nearly always slower than read speeds. While read speed may peak out at 60 sustained, write speeds usually never go above 40 on the fastest current hardware.

    I think apple did a very good job on the interface if you're sustaining those numbers!

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