The newly released iMac can be built with an optional 256 GB SSD. To complement this, the new iMac's also contains the Intel Z68 chipset:

Z68 mproves performance by putting files that are accessed often on the SSD.

Intel is coming out with a small SSD (20 GB), large enough to hold the Windows 7 operating system. This improves performance up to 355% depending on the application.

It strikes me as odd that Apple uses a (very expensive) 256 GB drive when you only need about 20 GB to get the benefit.

  • My late-2011 MacBook Air (which has SSD) is incredible snappy and I wonder if an SSD-iMac would see the same improvement?
  • Why use the 256 GB drive when a much smaller and cheaper would do it?
  • 1
    All other things equal, a larger SSD is better than a smaller one. Individual flash cells have a limited lifespan - you can only write to them a certain number of times before they become only readable. The larger the drive, the more flash cells to share the burden.
    – boehj
    May 8, 2011 at 17:42
  • 1
    Apple has built it's reputation by making it's products substantially better and not just incrementally better. I would speculate that either the bang/buck doesn't merit the small device or unannounced plans will make that small space less desirable in the near future. Great link on the Z68. Since apple underwrites many repairs for 3 years, new tech usually is tested thoroughly before it gets implemented to ensure user and shareholder satisfaction.
    – bmike
    May 9, 2011 at 16:17
  • Also apple.stackexchange.com/questions/22590/…
    – bmike
    Oct 22, 2011 at 11:55

3 Answers 3


The base model of 21" iMac only has one drive bay. So, a 20GB SSD wouldn't be very useful there. If you want an SSD, you have to get one big enough to hold all your data.

As for the 27" iMac and the upper model of the 21" (which have two drive bays):
Performance. Yes, you can fit the OS on a small SSD, but that's not the only thing that will benefit from being on a faster drive. Any operations that involve a lot of reading/writing will be faster if they're working with files on an SSD.
Convenience. Unless you set up your apps and Finder especially well, it will take a little more time to get to stuff on a secondary disk.
Quietness: SSDs don't chatter like HDDs. If you have both an HDD and SSD, you'll still hear the noise. Silent computers are nice, IMO.
Apple-ness: One of the things many people like about Apple computers is that things are mostly seamless ('Just Work'). Having one big, fast, quiet drive is more seamless and Apple-y than one small, fast, quiet drive and one big, slow, loud one.

One more reason Apple does it: Because they can: Add SSD. People buy SSD. Profit!

  • I wonder how many people will really buy it, considering you can get a Mac Mini for about the same price. May 9, 2011 at 18:18

You have to think beyond the OS. How many times are you booting up your computer (or putting it to sleep) a day?

Now how about launching and working with files? A lot of times a day I guess.

You don't want to keep ONLY your OS in the SSD, you want to keep often used apps, your music if it fits (and you access it very often) or your photos, etc. That's what takes time on a hard drive. On the other hand, since they are still not big enough to replace mechanical drives (and it they were the prices would be prohibitive) then you still have to have a traditional drive for long term storage.

Apps in SSD Drives launch in 1-2 seconds. Everything is faster.

  • Yes. But boot times aren't that ($600) important since rebooting iMacs are rare. But my late-2011 MacBook Air (which has SSD) is incredible snappy and I wonder if an SSD-iMac would see the same improvement. May 9, 2011 at 20:35
  • 2
    Re: Wondering if an SSD-enabled iMac will see an improvement: It absolutely will. May 11, 2011 at 19:59

If you have very important data, it makes sense to store that data onto an SSD rather than a traditional HD. So Apple giving you the 256GB SSD option totally makes sense to people like photographers who want to keep their Aperture library on the SSD rather than the traditional HD.

  • Hi, the failure rate of SSD greater than traditional drives, as shared by Jeff Atwood (who passes here occasionally) said: codinghorror.com/blog/2011/05/… So, go for SSD for speed rather than reliability. But, the speed is such an advantage that it justifies a more rigorous backup regime.
    – ianmayo
    Jun 10, 2011 at 9:22

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