Remember the good old days when you for a couple of minutes, changed battery, added memory and put the external hard drive? If you’re an Apple user for you all in the past, but upgrading your hard drive is still possible, and the developers until Apple allow us to do it. In 2010, Apple introduced its proprietary solid – state drives “blade” SSD. The company touts the speed of reading and writing, and reliability, but rarely explains the details of the technology used in SSDS, as these drives are designed only for Apple computers.

After many questions, the specialists of the service center Atiba decided to conduct their own research equipment. They had to become the “Apple detective” to uncover the secrets of these drives, because the deeper they looked, the more surprises were found. The details and results below.

Comparison of SSD interfaces

Each hard drive or SSD you used in the last 10 years, probably used a SATA interface, and has recently become circulated PCI Express interface. If you have an old computer and I think that many download and the long wait of the answer of the program is the norm, then perhaps you still have a disk with SATA interface. Time to increase the speed!

What is SATA?

SATA is a technology standard for connecting hard disks, SSDs and optical drives to the motherboard. The SATA standard has been used for many years and is the most common interface for connecting internal hard drives. The SATA standard has undergone three major changes, with the result that the connectors are identical in appearance (for backward compatibility), have double the bandwidth.

This can cause some confusion if you connect the hard disk support standard SATA III to SATA II since the interface of the second generation will limit the potential throughput of the disk. And in the case of SSD use SATA II is to deprive yourself of more than 200 extra MB/s read. But even when connected to SATA III memory capabilities of solid-state drives not fully disclosed.

What is PCIe?

Peripheral Component Interconnect Express (PCIe) is a standard computer bus with very high throughput and is the fastest bus available to the most computers. It is not surprising that manufacturers have moved to the PCIe SSD technology for.

As standard SATA, PCIe has undergone a lot of changes for many years and is still evolving at breakneck speed. PCIe 2.0 (probably the most common version PCIe) achieves a maximum speed of ~ 500MB/s with one channel bandwidth. This speed is slightly less than SATA III but PCIe has the advantage of using multiple channels to operate the connected peripheral equipment.

Lacking 2 channels bandwidth (~ 1 GB/s)? Double the number of channels to 4 and , if the connected device allows you to use them, you will receive twice the data rate. PCIe bandwidth can be increased to 16 and even up to 32 lines for a single device, but it is rare in the SSD, as it is primarily used for graphics cards. Most PCIe drives will have 2 or 4 channels bandwidth.

In 2011 was released the version of PCIe 3.0, in which the speed is increased not only by adding more channels. PCIe 1.0 and 2.0 use the coding 8b/10b for transferring data (same as SATA), which means that every 8 bits of data sent are sent in 10-bit linear code. In other words, 2 out of 10 bits are just the official data required for transmission of other data. 20% of these “throwaway” expenses eat real bandwidth of the interface, with the result that it is reduced by the same 20 %.

PCIe 3.0 has introduced a much more efficient encoding, 128b/130b, with the result that the efficiency approached 100% for the cost of potential bandwidth is only 1.5 percent.


Interface advanced host controller (AHCI) was created for HDD SATA drives. This mechanism allows you to use the built-in sequence of commands and hot-swappable. AHCI is a universal interface to work with SSD, when they have just started to develop, but for several years, it prevents data transfer speed.

Now on NVMe or Non-Volatile Memory Express. NVMe was designed specifically to work with the SSD, reducing latency and allowing you to transfer large amounts of data per unit time, allowing more efficient use of modern multicore processors. By the time of the release of PCIe 3.0 NVMe specification was required to use the full potential bandwidth of the drives.

Original Apple connectors

When Apple released its first slim SSD to MacBook Air at the end of 2010, still used the traditional technology of the SATA interface, at the same time, Apple abandoned the traditional form factors, SATA and mSATA, which were in most laptops of that time, instead of them choosing your connector which has never been used by other developers, neither before nor after. Releasing in 2010 MacBook Air, Apple has opened a new trend of development of proprietary connectors and form factors, which eventually captured the entire range of Apple and opened the era of drives, which along with their easy replacement, were difficult to purchase.

Many people mistakenly believe that connectors are one of the options in the M. 2 that you can find in many PCs, but in fact Apple had never used it. And unlike pinouts contacts called M. 2, Apple your connectors names were not given, so from now on we will simply refer to the connectors on the location of their contacts, as shown in the figure below.

The story of the release of the Apple SSD

1st generation Apple SSD: MacBook Air (late 2010 — mid 2011)

For releases of MacBook Air 11″ (model A1370) and MacBook Air 13″ (model A1369) of late 2010 — mid 2011, Apple’s desire to reduce the thickness of the already thin MacBook Air demanded a transition to a thin disk. Instead of using 2.5 inch SATA SSD, as in other lines of Apple products, or even 1.8-inch SSD, as was in the Original MacBook Air, Apple began to use a more subtle drive. In this drive, “generation 1” was used brand of 6 12-pin connector, redesigned mSATA III, limited 6 GB/s.

SSD the first generation was made Samsung and Toshiba, but as it turned out, the Samsung drives worked much faster. Both the drive worked in accordance with the stated Apple specs, but buyers of the MacBook Air participated in the “lottery SSD” because the owners of laptops with Samsung drives read and write took place about 1.5-2 times faster than the owners of Air with the Toshiba drives. Apple seems to have learned from this and subsequent generations of SSD has never been such a large difference between drives from different manufacturers.
MacBook Air these years, it’s possible to install third party SATA connector M. 2 2280 and size — for example Samsung EVO 860, through a special adapter.

2nd generation Apple SSD

The second generation of SSD Apple began to be used in laptops MacBook Pro Retina and iMac desktop computers. The disks of the second generation was faster than the previous, but still used the interface mSATA III come close to its maximum throughput.

The discs were characterized using two completely different forms; a short and wide disc generation 2A used in the MacBook Pro and iMac, and more long and thin disk generation 2B used in the MacBook Air. Both the drive 2A and 2B use the same mSATA interface 3 and the same type 7 + 17 pin. Despite using the same connectors and interfaces, the drives are not fully compatible, since the space allocated for the disk on each computer, just not designed for drives of a different type.

MacBook Pro (mid 2012 — early 2013)

With the release of the first MacBook Pro with a screen “Retina”, Apple has included a standard SSD in the MacBook Pro lineup and now, in fact, the only storage device is the drive with a 7 + 17-pin connector. SSDS generation 2A used in this MacBook Pro was manufactured with a capacity of 128, 256, 512 and 768 GB and was made by Samsung as well as SanDisk.

As for the 13-inch and 15-inch MacBook Pro uses the same disks, and on any of the laptops can be installed in any of the four SSD.

iMac (late 2012)

With iMac Late 2012 things were a little different. SSDS were only fitted with the Fusion Drive, they were connected into a single array with a traditional 3.5” and 2.5” standard SATA III. Apple’s Fusion Drive optimizes file storage, so files that are accessed more frequently, and system files are saved on the SSD, at the time, as most of the rest is stored on the hard disk.

Physically the system is implemented using a standard SATA connector and proprietary 7 + 17-pin. Fusion Drive can be disassembled at the software level and use the drives separately or on hardware — SSD socket can use any of the options generation 2A (128 GB, 256 GB, 512 GB or 768 GB), while the SATA connector can accommodate any SATA hard drive or SSD 2.5” and iMac 27” and 3.5”.

Important clarification: the 27-inch iMac always has 7 + 17 pin connector on the Board, and the 21.5″ has guaranteed this connector only if the iMac was originally with the Fusion Drive. Otherwise, you can find only empty space instead of the proprietary mSATA connector. However, iMac 21.5’, which are sold in Russia without the Fusion Drive, more often with SSD connector.

In such iMac and Retina Macbook Pro 2012 — Early 2013, you can install a SSD third party — for example the Samsung 860 series mSATA slot using this adapter or the drives of M. 2 2260 size through this.

MacBook Air (mid 2012)

As mentioned above, the CDs generation 2B have a different shape but use the same interface and connector as their counterparts of the generation of 2A. The speed of read / write 2B is considerably lower, probably due to technical limitations, and less disk space disk 2B.

Another result of the technical limitations is the inability to install ROM 768 GB. Samsung and Toshiba made drives generation 2B in variants 64 GB, 128 GB, 256 GB or 512 GB, all of them interchangeable in models MacBook Air 11″ model (A1465) MacBook Air 13″ (model A1466) release mid 2012

Here you can also use an adapter and put at least 2 TB SATA M. 2.

3rd generation PCI-e SSD Apple

With drives of the second generation, it became clear that the limitation of 600 MB/s for mSATA will not allow you to increase the speed, so in the next generation of storage, Apple began to use the PCIe 2.0×2, which resulted in a very substantial increase in performance. Performance varies greatly for different devices and ROMs, but the fastest configuration of the third generation can run more than two times faster than the fastest drives of the second generation.

In the third generation also saw the consolidation drive types: almost all drives are compatible with all models of Apple computers since mid-2013 to mid-2015.

SSD is not only compatible between different devices; in fact, different computers have the same drives. The SSD was made by Samsung, SanDisk and Toshiba, while on drives from all computers that were found are the same part numbers of the manufacturer. Samsung, except that added unique finishing (/ 0A2, / 0A4, / 0A6, etc.) to drives that are used in different devices, but all drives use the same controller flash memory, and testing showed a lack of difference in performance.

Solid state drives are the third generation have the same form factor (call it 3A), except for the SSD with a 1 TB (generation 3B), which, for the same length is approximately twice the width. All drives of the third generation use the same 12 + 16 pin connector and have a common interface PCIe 2.0×2, with the exception of SSD 1 TB PCIe 2.0×4, which is likely due to the large physical size of the drive, which allows for fewer engineering constraints.

All the disks of the third generation use technology AHCI, but the computers supplied with the discs 3 generations, also support SSDS NVMe, allowing an upgrade to the NVMe drives later generations.

MacBook Air (mid 2013 / early 2014)

In these MacBook Air in 11″ and 13″, using the same volumes of a disk of 128 GB, 256 GB and 512 GB option other than 64 GB, which was in earlier versions of the MacBook Air.

Interestingly,all the drives are limited to PCIe 2.0×2, all motherboard MacBook Air support PCIe 2.0×4, which makes it possible to upgrade to a faster 4-channel drives the fourth generation.

Mac Pro (late 2013)

Mac Pro late 2013 was the first model of Apple’s desktop with a PCIe SSD, and to the disappointment of many users, the first model, which supported only one internal storage device.

Mac Pro supports all of the drives (128GB — 1TB) SSD generation 3, but the stock version was completed drives with radiatorsmounted extremely durable heat-conductive glue. Apparently, if Apple engineers decided that it was necessary, so necessary. If you have the same opinion — you can stick the SSD on the radiator. But it is worth mentioning that without it, everything works fine, and internal testing showed absolutely no difference in temperature when using a SSD drive with the radiator and without it, even in the face extremely tough test.

Interface the SSD is connected from the motherboard of the Mac Pro and MacBook Air — supports connectivity PCIe 2.0×4, which improves performance with a later 4-channel drives. “Black cylinder” also supports the NVMe SSD and can be upgraded to discs 5 generations when working with MacOS 10.13 or later.

MacBook Pro (late 2013 — mid 2014)

The MacBook Pro late 2013 — mid 2014 support the all versions of the third generation drives, like the MacBook Air, andthe set includes drives PCIe 2.0×2, all the logical boards support 4-channel PCIe connections.

The MacBook Pro also supports NVMe Protocol and, like the Mac Pro requires macOS 10.13 or later.

iMac (late 2013 — end 2015)

In stock versions of 21.5-inch iMac was completed or SATA hard disk capacity of 1 TB or Fusion Drive 1 TB (128 GB PCIe SSD + 1 TB HDD SATA III), or a standalone SSD with a capacity of 256 GB. 27-inch iMac offered the same options, plus the Fusion Drive 3 TB (128 GB SSD and 3 TB SATA HDD) and a separate SSD capacity of 256 GB, 512 GB or 1 TB.

As in iMac free space significantly more than other Apple computers, you can easily deliver a wider SSD drive to 1 TB from 27” to 21”. As in the previous generation 27-inch iMac always has a PCIe slot on the motherboard, regardless of version. And his younger 21.5-inch sibling wasn’t so lucky. PCIe, 100% is only in case if it was originally configured with a Fusion Drive or a standalone SSD. If the connector on the motherboard is missing, just napati it will not work. There have been attempts to napati connector in iMac 21,5’ 2014, however, the startup disk is not enough electronic components on the Board, diagrams, need a donor. Or change the whole motherboard.

iMac 21.5″ and 27″ from late 2013 to 2014 to support NVMe drives, provided that you have installed MacOS 10.13 and newer, but the width of the connecting PCIe 2.0×2 negates speed advantages over ACHI.

Mac mini (late 2014)

At the end of 2014 appeared first Mac mini with PCIe SSD storage Apple, but its internal structure is not allowed to connect the drive to the motherboard directly. Place the drive in the Mac mini was on the back side of the plastic casing of the hard disk on top of the motherboard, which required a flexible ribbon cable to connect the SSD.

The tail has 12 + 16-pin female connector type a mom on one side and 40-pin connector that joins the motherboard. It was the first and last time Apple used a similar connector to the PCIe connections in their computers.

Connector present on the Board regardless of the store configuration was originally booked, so SSD PCIe can be added for all Mac mini for late 2014 , including through an adapter PCI-e for SSD from another manufacturer. The only — in configuration without Fusion Drive ribbon cable must be purchased separately.

Mac mini 2014 allows you to install NVMe drives starting with Mac OS High Sierra, but, as in iMac 21,5”, PCIe 2.0×2 will not allow them to be dispersed. The speed increase is modest 10-15%.

The fourth Generation Apple PCIe SSD

With the release of MacBook Air and MacBook Pro in early 2015, Apple introduced its 4th generation blade SSD with the same 12+16 pin connector, and 3 generations. So these discs can be a bit to disperse the maquis of the previous generation.

All SSD 4 generation used the PCIe 3.0×4, with the exception of the drive in a MacBook Air 11″, which put a PCIe 2.0×2 (called 4C), from the previous generation. You can refer to 128-, 256-and 512-Gigabyte drives 4 generation as a generation 4A, and more 1TB disk — on generation 4B.

Generation 4 is approximately two times increased speed of read and write compared to 3rd generation models. Overall, the fourth generation of drives was another qualitative step in the evolution of the Apple SSD.

This time the SSD was made by Samsung exclusively, with the exception of 4C Gen for 11″ MacBook Air, which was made Toshiba. The Samsung drives are generally referred to by the ID of the controller flash memory, UBX, or as indicated on the drive — SSUBX. This is a quick and easy way to distinguish the discs of the fourth generation of Samsung drives of the third generation, which is marked with ID SSUAX.

MacBook Air (early 2015 — mid 2017)

The latest release of the 11″ MacBook Air in early 2015 brought minor updates of some components, almost without changing the SSD. These drives were the only ones in the line of Apple products in 2015, which kept the PCIe 2.0×2 from the previous generation. The new drive was now detected in the system as “Apple”,the flash memory chips on the SSD indicate that manufacturers were Toshiba and SanDisk. Despite the 2-channel drive motherboard 11″ MacBook Air 2015 supports 4-channel PCIe 2.0 connection, i.e. can be upgraded with drives generation 4A of the other devices on the line this year. Exception — MacBook Air 11” with SSD on 512 GB from the factory. In this generation of SSD 4A.

13″ MacBook Air used drives generation 4A, the motherboard, like 11″Guo brother, used the PCIe 2.0×4. Despite this, the speed of read / write was at 90-120 % higher than the 2013/2014.
In these laptops does not have enough space for 1 TB and they are limited by the options of 128 GB, 256 GB and 512 GB.

MacBook Pro (early 2015 — mid 2015)

The MacBook Pro 2015 is also characterized by a relatively small update, but still the SSD has led to a significant increase in speed, especially for the 15″ model A1398, because there is PCIe 3.0×4 is up to 8 GB/sec.

And 13″ and 15″ MacBook Pro support the NVMe Protocol, and upgrade to SSD 5th generation causes a slight increase in speed for the 13″ model A1502, 15″ model A1398 with PCIe 3.0 connectivity really allows you to use the technology NVMe full. Reading speed increased by ~ 40 % and the write speed can be increased to ~ 60 %. The lineup this year was the most stable when you upgrade to the SSD via third party adapter from M. 2 socket on the Apple SSD. It is better not to save and take a quick PCIe 3.0 from Samsung. In the picture below the adapter kit with the drive 970 Samsung Evo.

iMac (late 2015)

In iMac late 2015, there was a lot of the same trends as in the previous models. The 21.5″ model has a PCIe slot on the motherboard unless the computer was originally configured for Fusion Drive or SSD Autonomous, otherwise it might not be, especially in computers from USA. Unfortunately many Fusion Drive capacity of 1 TB now includes SSD capacity 24 GB paired with SATA hard disk capacity of 1 TB. You are able to choose a stand-alone SSD with a capacity of 256 GB.

27″ there is a Fusion Drive with a 1TB HDD and SSD of 24 GB and a Fusion Drive for 2 TB and 3 TB already with the 128GB SSD. 27″ iMac is also sold with a standalone SSD with a capacity of 256 GB, 512 GB or 1 TB.

Interesting fact: this year, SSD to FD to 24 GB of PCIe 3.0×4 was also the first drive from the new NVMe Protocol! Disk capacity is actually 32GB, but 25% of the available space is reserved and unusable by the user. Apparently, it is made for use of this space for the dead blocks, as the SSD is used more often than in the conventional system.

The Fifth Generation

In the fifth generation SSDS Apple are a few major changes. Firstly — removable SSD only in the iMac and Macbook Pro 13” WITHOUT Touch Bar. Second — all of these drives support the NVMe Protocol, and all devices support connection PCIe 3.0×4. This means that the entire line indicators read/write on top and about equal.

There have also been changes in the form factor, a model with different types of SSD. One type will be called 5A, it uses absolutely new, much smaller form factor and a new 22 + 34-pin connector. Disk generation 5B is used 12 + 16 pin connector as previous generations. Despite the large connector on the disk generation 5A, which can improve performance, speed about the same. On iMac Pro installed SSD with connector 12+23 pin, smaller in size, we call them 5C.

MacBook Pro (late 2016 to mid — 2017)

At the end of 2016 Apple is releasing two versions of the MacBook Pro: a version without the touchpad and the version with touch panel (TB). Only 13″ MacBook Pro A1708 was offered in a version without the Touch Bar, and this is the only MacBook Pro that edition which has a removable SSD. In the rest of the drive is soldered to the motherboard and cannot be removed and replaced. The only way to increase storage on MacBook Pro with touch panel to replace the motherboard.

MacBook Pro A1708 without touch panel removable SSD drive is a new generation 5A. At the end of 2016 MacBook Pro proposed SSD-drive capacity of 256 GB, 512 GB or 1 TB, and in mid-2017 added option of 128 GB. Read speed ~2000 MB/s, write ~1900 MB/s. Solutions to replace third-party manufacturers and any adapter currently does not exist.

iMac (mid 2017)

In these devices has been used for the usual 12 + 16 pin connector on the motherboard connection interface PCIe 3.0×4, drives using the NVMe Protocol and operate at the highest possible speeds. There is an important difference between this iMac from the previous generation — PCIe is ONLY version with a Fusion Drive or SSD blade. And this applies to the 27” model too. The place of production is also irrelevant, so buying an iMac for an upgrade, should take into account this nuance. The speed of the drive read ~2200 MB/s, write ~2000 MB/s On the drives, from Samsung speed much more — 2800 MB/s read.

iMac Pro

At the moment the only iMac Pro is equipped with two PCIe 3.0 NVMe drives. Read speed is ~2500 MB/s, write ~3000 MB/s. It is unique in its kind SSD, as such, in the conventional sense, are not. These two scarves are removable only memory chips, while the role of controller PCIe/NVMe took the coprocessor T2. This means that replacement and upgrade is fraught with that iMac will not run, as the IDs of the new SSD will not be the same as in the controller memory T2.


Almost all the Apple computers you can replace the SSD at faster or just increase the size of the disk. For example, in the MacBook Air 2010 is installed slow drive,the laptop supports SATA III. It is sad that in the latest versions of the MacBook Pro with Touch Bar do not change it — maybe nothing at all because of the chip T2. Those who read to the end, a pleasant bonus — a discount of 10% promo code Insider for all types of labor and parts to upgrade your Mac from the service center Atiba in Moscow and St. Petersburg.