Hacking the mac mini to use 3.5" Harddrive via sata

Discussion in 'Mac mini' started by jjahshik32, Apr 28, 2008.

  1. macrumors 603

    Joined:
    Sep 4, 2006
    #1
    Man this is actually a great idea. If I can buy the $799 Mac mini and hack it with a 3.5" external harddrive with a 150GB 10k Raptor drive.. that would be freakin awesome.. has anyone done it here and if so... can you refer me to an excellent guide??
     
  2. macrumors 6502a

    iGrant

    Joined:
    Sep 20, 2006
    Location:
    Abingdon
    #2
    Yes it has been done before here is the link:
    http://www.macintouch.com/specialreports/minimonster/phase2.html

    It does give you a performance increase however your Mac is not in two parts . . . the computer itself and the hard drive down below. It even works better if you put the mac mini in a separate case altogether. I know there are people that have done it but I just can't find the links for it at the moment.

    -iGrant
     
  3. macrumors 65816

    Foxglove9

    Joined:
    Jan 14, 2006
    Location:
    Brooklyn, NY
    #3
    Wow nice work! I wonder if just using a firewire drive as a startup drive would give you almost the same performance as that hack, but without destroying your case and warranty (and maybe Mini).
     
  4. macrumors 6502a

    iGrant

    Joined:
    Sep 20, 2006
    Location:
    Abingdon
    #4
    Unfortunately no it wouldn't, not even Firewire 800 can give the same speed. Firewire is a wonderful connection but not nearly as fast as a SATA connection.

    -iGrant
     
  5. macrumors 68040

    squeeks

    Joined:
    Jun 19, 2007
    Location:
    Florida
    #5
    yeah doesnt matter how you look at it

    800mb/s (firewire 800) != 1.5gb/s (sata1)
     
  6. macrumors 6502a

    iGrant

    Joined:
    Sep 20, 2006
    Location:
    Abingdon
    #6
    Or even worse 800mb/s Firewire 800 != 3gb/s Sata II

    -iGrant
     
  7. macrumors 604

    Cave Man

    #7
    Not on a Mini.
     
  8. macrumors 6502a

    iGrant

    Joined:
    Sep 20, 2006
    Location:
    Abingdon
    #8
    Thats right they have 2.5 laptop hard drives which are only 1.5Gb/s Sata I . . . hey oops

    -iGrant
     
  9. macrumors 604

    Cave Man

    #9
    It's not the drive, it's the controller. My Mini, MBP and iMac 24" all have the same 1.5 gbps controller (Calistoga and Santa Rosa chipsets).
     
  10. macrumors 6502a

    iGrant

    Joined:
    Sep 20, 2006
    Location:
    Abingdon
    #10
    Thats what I meant. I have a Sata II hard drive pinned to 1.5gb/s limit in my Power Mac G5 . . . I will clarify next time ;).

    -iGrant
     
  11. macrumors G5

    CanadaRAM

    Joined:
    Oct 11, 2004
    Location:
    On the Left Coast - Victoria BC Canada
    #11
    But its nowhere near as simple as that.

    The performance you get from a drive is a combination of the interface real world speed (not the theoretical maximum speed), the drive's head access time rotational latency, and areal density, and the contention for resources (controller bandwidth, CPU cycles, etc)

    For starters, FW800 can push up to 80 MB/s if there is nothing else running on the Firewire controller.

    3.5" Desktop hard drives have only just broken the 100 MB/s barrier (WD Raptors, Samsung F1 and Western Digital Tornado). So the most a SATA connection can deliver from a single drive is the drive's maximum output -- so 150 MB/s or 300 MB/s are pretty much meaningless distinctions for a single drive, and most hard rives won't deliver more than the FW800 interface in any case.

    But wait -- laptop size 2.5" drives have a way lower output, because of simple geometry.

    Given the same RPMs (7200 RPM let's say), the amount of data that can be delivered depends on the density of the data on the disk platter, and the length of the track that passes under the heads in 1/7200th of a second. Track length = perimeter -- so a 2.5" drive's outer tracks are at a distinct disadvantage, being 7.8" in length (perimeter) vs. a 3.5" drive's 10.9" length (approximate numbers because the platters aren't exatcly that size)
    All else being equal, the laptop sized drive will be 28% lower in bandwidth.

    To add insult to injury, a drive's performance decreases as the drive fills up, and the data is written to the inner tracks of the drive. At 90% full, it's typical for a drive's inner track bandwidth to fall to half of the performace it was when empty. So that 104 MB/s performance from the Samsung F1 will drop to 55 MB/s or so when the drive is full --- and a small-capacity 2.5" drive fills up faster than a 500 GB or 750 GB desktop drive... 100 GB on a 120 GB laptop drive is almost full, but it hasn't even caused a 750 drive to break a sweat.

    So... that's a long way of saying that a Firewire 800 connection is not the limiting factor in most drive performance, and a 800 vs 1500 comparison with SATA-150 isn't relevant in most cases --- and a FW800 enclosure with a larger, high density (perpendicular recording) 7200 RPM 3.5" drive will likely outperform a 2.5" SATA-150 (or SATA-300) drive, especially a 5400 RPM drive that is 50% full already.
     
  12. macrumors 6502a

    Joined:
    Sep 9, 2007
    #12
    So FW400 (what a mini has) may be a limiting factor. Using the numbers from the above post, assuming FW400 is half the speed of FW800, some drives will are faster than FW400.

    I would think a good, fast FW400 drive would be faster than some of the internal SATA mini drives.

    An fast external 3.5" SATA drive should be faster than any FW400 drive.
     

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