External SSD for main drive on 2008 iMac possible?

Discussion in 'iMac' started by Turnpike, Feb 19, 2018.

  1. Turnpike macrumors 6502


    Oct 2, 2011
    New York City!
    I just came across an extremely well cared for 2008 24" iMac, and don't want to do a lot of opening-up and surgery on it if I don't have to, but the HD is so sluggish (previous owner said it was getting slower and slower over the years, and sometimes the beachball is there for 20 minutes just opening a web page).

    I will only use it for browsing, so is there a minimal upgrade possible where I could PLUG IN an SSD externally and run it off of that?

    I know there are speed limiting factors, like the SATA 2 and whatever the cable might bottleneck, but for just browsing, and externally connected SSD should work as an improvement, no?

    If anyone knows of an easy way to do this (it's worth me buying whatever cables and so on to do this, as I'd do it to more than one computer I have here as I needed them). Price for parts is not as much an obstacle as if they are external, I can always recycle them to the next early model computer.

    Thank you!
  2. shaunp macrumors 68000

    Nov 5, 2010
    Does it have thunderbolt? If so an external SSD with a thunderbolt connector should be fine.
  3. jerwin macrumors 68020

    Jun 13, 2015
    "fastest" port on the 2008 imac is the Firewire 800.
  4. Turnpike thread starter macrumors 6502


    Oct 2, 2011
    New York City!
    So would some kind of Firewire adapted down to the SATA be what I should use? Adapters and so on won't bottleneck it much? Or is there not that much different between Firewire 800 and USB2.0?
  5. jerwin macrumors 68020

    Jun 13, 2015
    you may may find this video useful..

    of course, blackmagic doesn't test random reads/writes.
  6. chabig macrumors 603

    Sep 6, 2002
    The best case for you is an external drive case with FireWire 800 and USB 3, like this: https://eshop.macsales.com/item/OWC/MSTG800U3K/
    Put an SSD in it today and when your iMac finally dies, you’ll still have a USB 3 drive for a new machine.
  7. nambuccaheadsau macrumors 68000


    Oct 19, 2007
    Nambucca Heads Australia
    Go with an internal SSD. Your iMac is not that difficult to open, has USB2 only and FW is not as good as an internal drive.

    Should you consider going this way do not buy a SATA III 6Gb/ps drive, particularly the Samsung EVO models as they are not backwards compatible with older Macs. Read the thread by Dan from ifixiit:-

  8. EugW macrumors 603


    Jun 18, 2017
    Here are my results running an iMac 2010 off Firewire 800. See post #12 in the thread.


    Yes it works fine, and can speed things up dramatically, but:

    1) You must buy a drive that has the option of AC power. Firewire power is too risky. See post #21 in that thread.
    2) You must buy a drive that is way larger than you actually need. If you fill up an SSD too much, you'll often run into serious performance problems.
    3) Firewire 800 works way better than USB 2.
    4) The cost of Firewire 800 enclosures these days is not cheap. Another option is to pay someone to install an internal SSD.
    5) If you reinstall the OS fresh on the internal hard drive, it may be tolerable just using the hard drive. You could always try that first.
  9. marzer macrumors 65816


    Nov 14, 2009
    Your best options are,

    1) Use an SSD ONLY if you install it internally

    2) If you are committed to the convenience of an external boot drive, use a hard drive.

    The reason is SATA 2 is not the bottleneck, it’s Firewire...FireWire 800 has a theoretical throughput of 100Mbps, actual throughput will be less, my experience is 80Mbps for external drives.

    Most modern 3.5” HDD operate at 100Mbps or faster, a lot of modern 2.5” HDD exceed 100Mbps. I have a 2.5” 1TB Toshiba that runs at 107Mbps, and a cheap 3.5” 3TB Generic that runs at 120Mbps. Both are faster than FW800. Especially for the price difference, you will be disappointed by the lack of performance of an SSD connected via FW800. In other words, you will not see any noticeable difference between a modern SSD versus a modern HDD when operating them on FW800.

    Even though it’s a SATA 2 interface, with a theoretical throughput of 300Mbps, a modern SSD will easily run in the 250-280 range. That’s probably four times the speed of the HDD the 2008 iMac originally came with.

    An internal SSD will be a 300% (or more) speed improvement over an internal HDD. Whether a modern SSD or modern HDD over FW, the performance improvement will be about the same, maybe 15-25% speed improvement over the stock drive. And to tell you the truth, that’s ONLY if the internal drive is failing to operate at original speed. Those drives back then tended to operate in the 70-80Mbps range anyway. So if it’s still operating as such, you may not see any improvement with an external FW drive.

    I’d recommend you bite the bulletproof, head over to iFixit for the instructional video and breath new life into that 2008 with an internal SSD. I did it with my 2009 iMac (SATA 2), upgraded it internally with a Samsung EVO, and the difference was fantastic!
  10. EugW, Feb 20, 2018
    Last edited: Feb 20, 2018

    EugW macrumors 603


    Jun 18, 2017
    The perceived speed up from an SSD is in large part dependent upon the speed up of random reads. So actually, FireWire works reasonably well. FireWire SSD random reads are way, way faster than internal HD random reads.

    In fact, in the benchmarks I posted in that thread, FireWire 800 SSD was over 20X faster than internal 7200 rpm HD, for random reads.
  11. Fishrrman macrumors P6


    Feb 20, 2009
    A 2008-vintage iMac has USB2 (not USB3) and firewire800.

    Here's what I'd suggest. Before going further, I REALIZE that it won't boot as fast "as if it were USB3", so others don't have to jump in and remind me.

    Get a small (250gb) USB3 external SSD like this:

    You intentionally DON'T want to spend a lot of money on this.

    Plug it in, initialize to HFS+ with journaling enabled, then set it up to become your external boot drive.

    It's not going to boot much (any?) faster than the internal drive. This is due to speed limits of the USB2 bus.

    BUT... once you get up-and-running, things should go better. Possibly much better.

    This will revive the old iMac and ought to make it usable and keep it going until it has a serious internal failure (other than the hard drive). And when that happens, just disconnect the USB3 SSD and repurpose it to some other task...
  12. EugW macrumors 603


    Jun 18, 2017
    A FireWire 800 SSD is quite a bit faster than a USB 2 SSD. And more importantly, a FireWire 800 SSD feels quite a bit faster than a USB 2 SSD. I’ve already tried it. Check out post 11 in that thread of mine I linked. Again, it has to do with the random reads, and I suspect that USB 2 is adding a fair bit of latency to the reads.

    Here are my results:

    4K random read (internal HD): 0.7 MB/s
    4K random read (USB 3 SSD): 7 MB/s <-- running at USB 2 speeds
    4K random read (FW800 SSD): 18 MB/s

    With the same USB 3 SSD running through USB 3 on another machine, I'd get 20 MB/s for 4K random read, so it's clear that just using the USB 2 interface instead of USB 3 seriously cripples the random read speeds, even though USB 2 can theoretically hit much higher speeds. Indeed, with sequential transfers, I could get up to 29 MB/s over USB 2 with the same drive, but as mentioned, responsiveness is dependent much more on random access speeds, not sequential transfer speeds.

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11 February 19, 2018