I'm hearing the iMac is pretty slow.

Discussion in 'iMac' started by imjoee, Dec 2, 2012.

  1. imjoee macrumors 6502


    Jun 12, 2012
    I was deciding to get the base model 21.5" because money is tight for me. I have been hearing the hard drive on the base model is extremely slow, what kind if external hard drive should I buy and what brands should I get? And how does a external hard drive work? I've never had one, I've been seeing SSD externals? How do they work, do I plug it in? Does it automatically sync my stuff from my computer to the external drive? Please help, I want to know what I'm spending my money on. Thank you for your responses!
  2. MeFromHere macrumors 6502

    Oct 11, 2012
    "Extremely slow" is subjective and perhaps somewhat misleading. If you're concerned about disk speed, it might be a good idea to wait for a week or so; there should be very complete benchmark results available by then.

    So far, I've seen a handful of people complaining about the disk based on a single specification -- the rotation speed. The 21.5" iMac uses disks that spin at 5400 RPM. These are pretty common in laptops, but they aren't usually used in high-performance desktop systems any more. Desktops are more likely to use 7200 RPM disks. 7200 RPM drives are typically louder, hotter, and use more power than 5400 RPM disks; that's why laptops tend to favor 5400.

    If everything else is the same, a 7200 RPM disk will transfer data about 33% faster than a 5400 RPM one. That difference is the basis of the "extremely slow" complaints. Real performance depends on many other factors, including cache size, seek time, interface type and speed, to name just a few. Performance also depends on the type of workload. I don't think we know all the detailed specs for the drives in the new iMacs yet. So it's pretty hard to predict just how they will perform. That's why I suggest waiting for some competent, complete benchmarks.

    What kind of computer are you using now? Do the disks seem slow for your usual tasks? The base model iMac might be just fine for you.

    You have a few options if you want to add an external disk for better performance. You can use a conventional hard disk with USB 3.0, Firewire, or Thunderbolt interface. (Note that Firewire will require an adapter with the new iMacs, since they don't have Firewire ports.) You'd want to make sure to buy a disk drive with good specs -- 7200 RPM, moderate to large cache, and a good interface. Unless you already have a Firewire drive or can get one very cheap, USB 3.0 is a better buy these days. Thunderbolt is an expensive interface and is overkill for a regular disk drive. Most of these 7200 drives need an enclosure with a cooling fan, and they aren't all quiet. This kind of disk could get you maybe 30% better improvement than the built-in disk. Maybe somewhat more or less.

    You'd get MUCH better performance, for quite a bit more money, by getting an external SSD. If you're serious about the base iMac, you probably won't want to spend the money for a large SSD, so you'll have a pretty small disk compared to the built-in 1TB one. A good SSD would be limited by a Firewire interface, so avoid that. USB 3.0 is adequate, and mostly affordable. The best SSDs are faster than USB 3.0, so for best possible performance you probably would need Thunderbolt. A top-end SSD with Thunderbolt is expensive; you might do better with the higher-spec iMac with a fusion drive.

    For a lot of people doing general-purpose computing, the higher-spec 21.5" iMac, upgraded with a 1 TB Fusion drive, is a very, very good compromise. The Fusion drive combines a 1 TB hard drive with 128 GB SSD. The OS tries to keep all the most-used data on the SSD. (Until you use more than 128 GB, ALL your data is on the SSD.) Depending on workload, you'll get maybe 90% of the performance of a pure SSD on average. You still have 1 TB+ capacity, and the cost is MUCH less than a 1 TB SSD would be. (There are some specialized workloads where a Fusion drive won't be much better than a normal drive.) The safe recommendation for most people is to upgrade to the Fusion drive. The only good reason NOT to get fusion is if it breaks your budget. You might spend less with a base iMac plus an external disk, but the difference might not turn out to be worth the time and trouble.
  3. imjoee thread starter macrumors 6502


    Jun 12, 2012
    Lastly after reading all your helpful info, I decided to go with the low end 21.5in iMac with a external elgato 120gb SSD thunderbolt, definitely helps me with my budget an not to much of a hassle, which will be saving me about 300$.

    Thanks again for the helpful response!
  4. yezza macrumors regular

    Mar 12, 2008
    Excellect, unbiased and informative post.

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