Apple launched updated MacBook Air models in October of 2010, featuring new, compact, and (originally) proprietary form-factor solid state drives (SSDs). The SSDs have so far only been available to OEMs directly from Toshiba, despite the fact that the SSD is the only user-replaceable part in the MacBook Air. It took a few months, but long-time Mac upgrade source Other World Computing stepped up to offer three upgrade optionsbased on fast Sandforce controllers.
OWC's Mercury Aura Pro Express SSDs (say that three times fast) come in 180GB, 240GB, 360GB, and 480GB capacities. So we installed a 240GB Mercury Aura Pro Express that the company lent us into an 11" MacBook Air in order to see how difficult the upgrade process is, and to put the drive through its paces and see what kind of performance gains are possible with the Sandforce-based design.
Installation: pentalobe driver included
As we said earlier, the SSD is pretty much the only user-serviceable part inside the latest MacBook Air. The battery can technically be swapped out too, but so far, the only parts are available directly from Apple, which means a trip to the Genius Bar. Everything else is soldered directly to the logic board, including the RAM.
The installation process for the drive itself is very straightforward: remove some screws, remove the bottom plate, take out the OEM SSD, swap in the OWC SSD, and put the bottom plate back on. Depending on your comfort level, you should be able to do it in 15-20 minutes.
The main hurdle with installation was that there were no external drive cases for the special small-outline SSD modules that Apple uses in the MacBook Air. With standard 2.5" notebook drives, you could put the original in an external case, install the replacement, and clone the external drive to the new drive. OWC told Ars that it plans to offer an external USB enclosure sometime soon, but until then, replacing the SSD means a full backup and restore to an external drive will be needed. It's not difficult at all, but it can be more time-consuming than one would hope.
We'll detail the process we used, noting a couple caveats along the way.
First, you will need an OWC Aura Pro Express SSD drive, your MacBook Air, an external USB 2.0 backup drive, and pentalobe and T5 torx drivers (included with the Aura Pro Express). You'll also need some kind of backup software; we used Mike Bombich's excellent donationware app Carbon Copy Cloner.
We recommend an anti-static mat and/or grounding wrist strap if you have them—you can do without, but the usual warnings about static discharge ruining your sensitive electronics applies here. We also recommend using either loops of tape affixed to your work surface or a small magnetic strip to keep track of the 11 tiny screws you'll be removing.
Step 1: Backup
First, you'll want to back up the data on your MacBook Air's current internal SSD. There are a couple different methods for backing up and restoring. You could make a Time Machine backup, use the recovery USB drive supplied with your Air to reinstall Mac OS X, and restore from Time Machine. You could also do a similar method with other backup products, but restoring from the backup might require installing additional software.
We used our usual method of creating a bootable backup using Carbon Copy Cloner. A portable 120GB USB2 Western Digital hard drive served our purposes here, as the stock 128GB SDD was only about half full. CCC created an exact copy of the Air's 61GB of data in about 54 minutes.
Just to be extra safe, we booted the Air using the cloned drive to check that the data was intact. After hearing the Air's startup chime, hold down the option key. You'll get a display of valid boot drive icons to choose from; choose your external cloned drive. Be prepared for a wait—booting from an external drive is going to be significantly (even painfully) slower than you're used to. Once you're sure everything is working as it should, shut down the MacBook Air. Be sure to disconnect any external peripherals and the power adapter.
Step 2: Remove the bottom panel
The MacBook Air has a thin panel of aluminum covering the bottom. You'll need to remove 10 tiny pentalobe screws to get the panel off. Thankfully, OWC includes a five-pointed star driver with the Aura Pro Express.
Turn the MacBook Air upside down with the hinge facing away from you. At the top, there are two longer screws that go all the way through the thickest part of the casing. We recommend removing these first. The driver that OWC includes doesn't appear to be a perfect fit, so push the driver down firmly, and carefully unscrew these two screws.
The remaining eight screws are very short, and all appear to be the same. However, we discovered during reassembly that some of the screws seemed to fit better in certain holes. Our advice is to keep track of which screw came out of which hole, and be sure to put them back in the same hole later. Again, you'll want to push the driver down into the screw firmly, and carefully remove the screws to avoid stripping the tiny pentalobe heads.
Once all 10 screws are removed, lift the bottom panel off.
Step 3: Remove the stock SSD module
The stock SSD—in our case, a Toshiba-made 128GB module—is located directly above the large, flat Li-ion battery and below the Core2 Duo and NVIDIA 320M. It is held in place with a single Torx T5 screw. Use the supplied Torx driver to remove this screw.
WARNING: It is possible to puncture the cells that make up the MacBook Air's battery if something sharp enough comes in contact with a cell's thin membrane with enough pressure behind it. Not only will that mean a trip to the Genius Bar to replace it, lithium ion polymers can react violently with air, causing fires or explosions.Do not drop your screwdriver on the battery!
The SSD connects to the logic board with a small, flat connector, similar to mini-PCI but smaller still. This connector is specifically made to connect SSDs using an SATA interface. Carefully lift the right edge of the SSD and pull slowly but firmly to remove the module. You may find that it comes out easier if you wiggle it slightly back and forth.
Step 4: Install the Aura Pro Express
Now you just need to do the first three steps in reverse. Remove the Aura Pro Express from its anti-static bag. You'll notice that the Sandforce 1200 controller has a large thermal pad on top. This pad will make contact with the MacBook Air's bottom panel to dissipate additional heat. While using the Aura Pro Express over the course of several days, though, the bottom of the MacBook Air didn't get noticeably hotter compared to using the stock drive.
For what it's worth, OWC's drive models use Hynix flash chips, while Apple's OEM drive uses Toshiba flash, and reports indicate that some MacBook Airs are now shipping with Samsung-made modules with Samsung flash chips. We noticed that the DRAM soldered to the MacBook Air's logic board was made by Hynix as well.
Holding the tiny SSD at a slight angle, work the connector into the slot on the logic board. Press firmly but carefully on the rear of the module. Like most internal PC parts, you'll probably need to push a little harder than you think.
Once the module is firmly in the slot, reattach the small retaining screw. We encountered some noticeable bending of the module when reattaching the screw. An OWC spokesperson told Ars this was normal—a result of the reverse-engineering process—and the flexing didn't seem to interfere with either the SSD's operation or with any other internal components.
You can see that the stock SSD only has flash chips on top, while the Aura Pro Express has an addition bank on the bottom. This may be one reason why Apple only specs the 11" MacBook Air up to 128GB, and likely the cause of the board flexing we noticed when tightening down the Aura Pro Express.
Step 5: Re-attach the bottom panel
Replace the MacBook Air's bottom panel. Remember that the two longer screws go at the top near the hinge, and that the smaller screws seem to work best when going back in the original hole they came out of. When driving the screws back in, press down firmly with the driver and carefully turn the screws to avoid stripping the pentalobe heads.
Step 6: Format and clone
With your new SSD installed, there are still a few maintenance tasks to complete before you're back up and running. You'll need to boot from your external backup (or the MacBook Air's recovery USB key). Right away you will get a scary warning that the "disk you inserted is not readable by this computer." The Aura Pro Express doesn't come formatted, so you'll need to use Disk Utility to format (and optionally partition) it before using it with Mac OS X.
Launch Disk Utility, and you should see the OWC drive in the list on the left. Select it, then click on the Partition tab. The default option is a single partition, formatted as "Mac OS Extended (Journaled)" (aka HFS+), with a GPT partition map (the type required to boot Intel Macs). Type in a name for the drive and hit Apply. If you understand terms like "partition map," then you know what to do here if the default options don't suit your needs.
Once formatted, you'll need to restore your data to the Aura Pro Express. Using Carbon Copy Cloner, we just cloned the external drive to the Aura Pro Express. We found this process was slightly faster than cloning to the external drive—about 42 minutes. Once cloned, you can reboot using the option key to select your new internal drive and you should be up and running in a matter of seconds.
All told, the entire process took a little over two hours, including taking pictures of everything. The actual drive swap itself took about 20 minutes; the rest of the time will vary depending on how much data you have to move around, what restore process you use, and how fast your external drive is.
Benchmarking: faster than fast
With the Aura Pro Express installed, the 11" MacBook Air had nearly double the stock capacity, 240GB versus the stock 128GB. OWC's SSDs use a few gigabytes for "over-provisioning," extra storage blocks used to increase write performance and reliability—the latter by automatically compensating for inevitable bad blocks that fail over the life of the drive.
| Standard drive size* | OWC Aura Pro Express | Over-provisioning | |
|---|---|---|---|
| *based on standard NAND flash chip sizes | |||
| 184GB | 180GB | 4GB | |
| 256GB | 240GB | 16GB | |
| 384GB | 360GB | 24GB | |
Beyond the boost in capacity, the Aura Pro Express's Sandforce controller offers a noticeable speed boost. After booting the Air from the Aura Pro Express for the first time, everything seemed just the tiniest bit faster. The subjective feeling is significant, because the 11" MacBook Air already feels much faster than a machine stuffed with a spinning platter.
Subjective feelings aside, however, hard data backs the claims that OWC's drives outperform the stock models. We used Intech Software's QuickBench, which can run a series of read and write tests on any drive attached to your Mac. We ran a battery of tests with small, medium, and large data sets. Each test was run 5 times and values were averaged. Data from the medium (2-10MB) and large (20-100MB) data tests were averaged together, though values weren't significantly different for those two tests.
Standard speed tests use variable small data sizes, from 4K up to 1024K, and record read and write speeds for data located sequentially on the drive and bits that are scattered randomly. The stock Toshiba-made drive performs admirably in sequential reading and writing, topping out at 211MB/s and 190MB/s respective. Random speeds were much less impressive, so if you are working on a file that is fragmented across the drive, there will be a measurable performance hit.
Oddly, the stock drive seemed to take a nose dive in random write performance with 1024K data chunks. This anomaly was repeated through several test runs, even when enabling asynchronous I/O and caching options, and we honestly can't explain the results. Our best guess is that it has something to do with a design choice in the Toshiba-made controller, though it's worth noting that larger data sets didn't appear to suffer from the same issue.
The Aura Pro Express definitely outperforms the stock drive, however. Sequential reads topped out at 243MB/s, while sequential writes peaked at 199MB/s. That's a 15 percent read performance boost and 5 percent write performance boost over stock. Random read speeds trailed at the smallest data sizes, but nearly catches up to sequential reads at 1024K. Random writes are as fast as sequential writes, thanks to the Sandforce's over-provisioning. As befits its reputation, the Sandforce 1200 controller delivers on its speed promise.
For completeness sake, we also ran a second set of tests using QuickBench's asynchronous I/O and caching options. An Intech engineer explained to Ars that the tests normally run with one read or write operation at a time, but Mac OS X is capable of queuing multiple read or write operations asynchronously for better performance in some cases. Furthermore, data that can be delivered from a drive's cache can offer a speed boost in some cases as well, though both async I/O and caching generally offer much larger improvements on traditional hard drives. Enabling both options during testing showed practically no difference in read speeds, but did improve write speeds slightly.
Conclusion
The OWC Mercury Aura Pro Express is effectively the only upgrade option on the market for Apple's latest MacBook Air models. (Asia-based PhotoFast attempted to offer a replacement option late last year, but got shut down by Apple legal, presumably due to IP infringement of some kind.) Considering this fact alone, it's nice to have an option at all.
Installation is pretty easy, though it does require an additional backup drive to shuffle your data around. The process will likely be sped up significantly if and when OWC offers an external enclosure for the small-outline SSD modules. Another benefit of an external enclosure is that it allows you to continue to use the module you replace in the MacBook Air—otherwise it sits in a drawer collecting dust until it gets tossed or perhaps sold on eBay for pennies on the dollar.
The real pain with the Aura Pro Express is the price—these SSD modules pack a lot of expensive NAND into a tiny space, and the price is commensurate. A 180GB drive costs $479.99, the 240GB drive we tested is $579.99, the 360GB drive is a whopping $1179.99, and the 480GB drive is a bank account-busting $1579.99. On a cost-per-GB basis, the 240GB drive is the best value, but if you need more storage than that, the 360GB and 480GB drives are your only (costly) alternatives.
For comparison sake, though, it's worth considering what Apple charges for the higher capacity SSD options on the MacBook Air. The 11" model starts at $999 with a 64GB SSD, and Apple doubles that for just $200. The 13" model comes stock with a 128GB SSD at $1299, and bumps the drive to 256GB for an extra $300. If one of these stock options will suffice, you'll save money with these build-to-order options. If you do plan to upgrade, though, opt for the low-end version and put that extra $200-300 towards an OWC Aura Pro Express.
While our benchmark tests revealed consistently faster performance from OWC's Sandforce-based SSDs over the stock Apple drives, we have also heard reports that some MacBook Airs are shipping with Samsung-sourced SSDs that offer performance nearly as fast as the Aura Pro Express. Though there was a slight noticeable performance difference in our regular use over the Toshiba-made drive, in particular when launching apps or scanning large collections of images, we don't feel like the performance advantage is necessarily worth the cost. (If utmost performance is a concern, you probably aren't using a MacBook Air anyway.) We feel the primary reason to consider spending the cash on a Aura Pro Express is the extra capacity, and OWC is offering something you just can't get from Apple or elsewhere.
Further reading
- The future of notebooks: Ars reviews the 11" MacBook Air (arstechnica.com)
- iFixit finds MacBook Air full of pesky screws, proprietary parts (arstechnica.com)
Flowing Links From
<http://arstechnica.com/apple/reviews/2011/05/review-supersize-your-macbook-air-ssd-with-owcs-aura-pro-express.ars/1
http://arstechnica.com/apple/reviews/2011/05/review-supersize-your-macbook-air-ssd-with-owcs-aura-pro-express.ars/2
http://arstechnica.com/apple/reviews/2011/05/review-supersize-your-macbook-air-ssd-with-owcs-aura-pro-express.ars/3
http://arstechnica.com/apple/reviews/2011/05/review-supersize-your-macbook-air-ssd-with-owcs-aura-pro-express.ars/3
http://arstechnica.com/apple/reviews/2011/05/review-supersize-your-macbook-air-ssd-with-owcs-aura-pro-express.ars/5>
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