Anyone who has had the opportunity to upgrade a Mac by replacing the hard drive with an SSD can confirm the actual speed improvement that can be achieved. SSD units only integrate electronic components. They do not have the mechanical parts found in traditional hard disks (platters, motors, head arm, and heads) and consequently are more reliable and much faster in reading/writing. They allow you to start the computer, both a Mac and a PC, first, start applications faster, allow them to read/write temporary files in a much more reactive way.
However, let’s start from the beginning and see what an SSD is. We explain roughly how they are made and how to install one on the Mac. The information we provide is largely useful even for those wishing to do the same operation on a PC.
What is an SSD?
SSD is the abbreviation for Solid State Drive. These drives are made using NAND Flash or DRAM memory chips in place of traditional platters and other mechanical components normally found in traditional hard disk drives (HDDs). SSDs are an evolution in computer storage memory, ensuring greater speed, quietness, and cooling capacity than the technology previously used in hard drives.
As mentioned, thanks to the absence of moving parts, SSDs also guarantees greater durability and greater reliability than hard drives.
What are the benefits of an SSD?
The SSD increases the reactivity of the system that will offer a greater startup speed, in the loading of application and at shutdown. SSDs not only boost performance, they can also be used to breathe new life into old systems. An SSD saves the cost of buying a new computer by bringing new life to an existing one.
SSDs do not have the physical footprint limitations of traditional hard drives. The platters of the HDDs have a circular shape (similar to a CD), and the time required to access the data contained in the center of the circular area is longer than that required to access the data located on the outermost area of the platter. The SSDs have instead a uniform access time over the entire area of the drive.
The performance of HDDs is also affected by the level of data fragmentation. The performance of SSDs is not affected by this phenomenon, even when the data is not stored contiguously. Other advantages of SSDs are lower power consumption compared to HDDs and silence (due to the absence of mechanical components and moving parts).
What are the disadvantages of SSDs compared to HDD?
HDDs currently cost less per gig than SSDs. This is due to the fact that traditional hard drives are sold in capacities of 500GB up to 10TB (although we can also find 12TB) while SSD drives are sold with capacities starting from 64GB and up, up to a maximum of about 4000GB (4B). Another disadvantage of SSDs is related to the difficulty of recovering data in case of failure.
A recovery intervention in case of problems is complex since the data on SSD / Flash memories are stored with completely different logics compared to traditional hard disks. For the latter there are various companies that offer data recovering services; far fewer companies are able to intervene in the event of SSD failures.
Traditional HDDs are the ideal solution when the needs require the use of drives with large storage capacities, in the order of terabytes, while SSDs are the preferred choice of those who have as their main objective the performance. SSDs are typically used as a boot device, with the operating system and the most frequently used applications, while the data is stored on conventional hard disks.
Can SSDs be used on any Mac or PC?
2.5 ″ solid state drives can be used on any system that supports SATA II and III interfaces. (SATA 3 Gb / s and 6 Gb / s). SSDs with this interface are typically built with a 2.5 “form factor (reminiscent of traditional 2.5” HDDs). On Mac/PC with this type of interface just replace the HDD and put the SSD drive. Macs and PCs of recent generation support connectivity and SATA III protocol up to 6Gbit/s (which corresponds nominally to 600MB/s. The throughput is lower and still drops in the case of an older Mac/PC with SATA II connection.
On recent-generation Macs, SSDs with SATA connectors are not installed. However, series units with connectors that allow you to obtain read/write speeds higher than those that can be obtained with SATA connectors. If you intend to replace an SSD on Macs that use connectors of this type, you will obviously have to buy specific drives.
What are the differences between SATA I, SATA II, and SATA III?
- SATA I (version 1.x), formally known as SATA 1.5Gb/s, is the first generation SATA interface running at 1.5Gb/s. The supported bandwidth is up to 150MB/s.
- SATA II (version 2.x) formally known as SATA 3Gb/s, is a second generation of the SATA interface running at 3.0Gb/s. The bandwidth speed supported by the interface reaches up to 300 MB/s.
- SATA III (version 3.x) interface, formally known as SATA 6Gb/s, is the third generation of the SATA interface running at 6.0GB/s. The bandwidth speed, which is supported by the interface, reaches up to 600MB/s. This interface is compatible with the SATA 3Gb/s (revision 3.x) interface.
The SATA II specification ensures compatibility so drives of this type can work with SATA I ports. The SATA III specification offers backward compatibility with SATA I and SATA II ports. However, on older generation interface computers the maximum drive speed will be slower due to the lower speed specifications of the SATA port.
Drives that support SATA 6Gb/s interfaces when connected to a SATA 6Gb/s port, can typically achieve up to 550 / 520MB / s in sequential read and sequential write speeds respectively. When the SSD is connected on a SATA 3Gb/s port, it can reach 285 / 275MB / s of sequential read and sequential write speeds respectively.
How do you install an SSD on a Mac or PC?
First, you need to check the type of interface used by the disk currently in use. If you have a traditional hard drive with a SATA II/III interface on your Mac/PC, you can buy an SSD with a SATA III interface and install it in a very simple way instead of the traditional HDD.
On recent Macs you can check the type of interface used on your current disk in this way:
- Select “About this Mac” from the Apple menu
- Click on “System Report”
- In the window that appears, select in the left column the item “SATA / SATA Express”
- Check (in the right section) the serial ATA device present. It indicates the type of media currently installed and also the physical interconnection used (eg PCI or SATA).
Which SSD is compatible with my Mac computer?
You need to check the type of hard drive installed on your computer to determine the appropriate drive, whether it uses a 2.5 ″ or 3.5 ″ form factor. Most SSD manufacturers offer 2.5 “SATA internal drives, others with mSATA connector, with other connectors and form factors, and with mounting kits or brackets to fit 2.5” drives into bays. 3.5 ″.
Can SSDs be installed on all iMacs?
In the most recent Macs, Apple has abandoned the SATA III connection for dhsci connections, to take advantage of the even faster PCI-Express connectivity speed. Installing an SSD is definitely a feasible task if your Mac was designed for the 2006-2013 timeframe. Newer Macs come with Apple-designed SSDs as standard. The costs of replacing these units are high and vary from machine to machine.
How do I install an SSD in older Mac Pros (older than 2013)
Older Mac Pros can accommodate up to four 3.5 ″ SATA drives. There are adapters that allow you to convert SSD from 2.5 “to 3.5”. In HDD bays, you can add new drives or replace existing disks. Solid state drives (SSDs) come with adapters that allow them to be installed in 3.5-inch drive bays.
For installation:
- Simply open the Mac Pro by removing the side panel.
- Lift the latch to release the drive carriers.
- Pull the carrier out of the hard drive bay.
- Join the solid state drive adapter to the stock carrier in the computer.
- Place the drive carrier over the SSD adapter. Make sure the drive connectors are facing the rear. Slide the carrier over the rails and into the bay until it touches the hard drive connectors. It should fit fully and securely into the bay.
Is it possible to change the SSD on the MacBook Air and newer MacBook Pros?
The basic MacBook Air integrates 128GB PCIe SSDs and is configurable with 256GB or 512GB PCIe SSDs when purchased. Manufacturers such as Transcend, OWC, and others provide specific kits that allow you to replace the stock SSD with larger drives than those offered by Apple. Transcend, for example, offers 240GB, 480GB, or 960GB drives. This includes a box that allows you to reuse your existing SSD as an external drive. The same thing does OWC with its Aura models (in various versions depending on the speed of the discs.
Products of this type are offered for MacBook Air 13 ″ 2008 (drives with ZIF connector), MacBook Air 13 ″ late 2008-2009 (drives with SATA connector), MacBook Air 11 ″ and 13 ″ 2010-2011 (SSD onboard with socket), MacBook Air 11 “and 13” 2012, MacBook Air from mid 2013-2017 and MacBook and MacBook Pro from 2006 onwards, including MacBook Pro Retina 13 “and 15” from late 2013 to mid 2015 (with PCIe connector ).
You cannot change the SSDs on MacBook Air 2018. Not even on Mac mini 2018 because they are soldered to the motherboard.
For some machines, replacing the SSD with a larger one can be a problem. Apple uses proprietary firmware which makes it very difficult for manufacturers to offer replacement components. The advice is to carefully check the availability of the products and their compatibility, which changes from month to month.
