MACBOOK AIR SSD TEARDOWN
Being new to the Mac world, I hadn’t a clue that the MBA was screwed together by ‘five point pentalobe’ screws, much less that the pentalobe is yet another part proprietary to Apple. Things became even more difficult after I found someone who had a pentalobe screwdriver, only to discover that there were different size pentalobe bits for an iPhone and MacAir. Who would of thought?
Not wanting to wait until receipt of a pentalobe screwdriver a week or two down the road, we visited our friends at the Mac Outpost who were kind enough to help get the back plate off of our new MBA and were we in for a shock? What we believed to be a Toshiba branded SandForce SSD was actually a Samsung ‘gumstick’ style PM830 mSATA SSD.
This Samsung PM830 SSD comprises of Samsung’s own S4LJ204X01-Y040 3-core ARM controller, Samsung 256MB DDR2 SDRAM cache memory (K4T2G3140F-MCF7) as well as eight pieces of 32GB Samsung K9PFGY8U7B-HCKO Toggle mode NAND flash memory.
The differences between this SSD and this PM830 review are the interface and PCB style as well as capacity of each module of NAND. This SSD is ONLY compatible with Apple products released at the same time as our MacAir with a mid-2012 build date.
Through use of Crystal DiskInfo, we can see that Apple has placed their name on the SSD, listing it as an ‘Apple SSD SM256E 251GB’.
The SSD also displays very limited SMART attributes and that SMART, 48bit LBA, AAM, NCQ and TRIM are supported features. It bears mentioning once again that this SSD has been partitioned into equal sizes for two different operating environments, each of which don’t recognize or have any control over the other.
OSX AND TRIM SUPPORT
An SSD works slightly different than a hard drive, in that, information cannot simply be over written once deleted. The process is a bit more complicated, whereas when information is deleted it actually isn’t. The index to the information is removed which fools the operating system into believing the space is free. With an SSD, the space must be cleaned of that information prior to new information being stored, or performance of the SSD slows significantly if it has to do it at the time. In a nutshell, that is what TRIM accomplishes behind the scenes to ensure your system remains at top performance, performance that is magnitudes above that of a hard drive.
OSX supports TRIM, however, Apple is a very proprietary animal. As of OS X 10.7, Apple has cut off TRIM to third party SSD manufacturers and only supports Apple branded SSDs to which, the ONLY such SSDs supported and guaranteed to have TRIM working by default on the mid-2012 MBA are the Apple branded Samsung 830 we will evaluate here and the Toshiba SandForce Driven SSD we hope to be evaluating soon enough
For those with third party SSDs that don’t enjoy ‘drinking the Apple koolaid’ so to speak, TRIM Enabler 2.0 is there for you and free of charge, a great utility that also confirms that TRIM is functioning for the rest of us Mac users as well.