Three SSD Interface Types: Which One Should You Go For?

SATA SSD Interface:
The 2.5-inch Serial ATA drive is the archetype of solid-state drives (SSDs). To date, there have been many forms of SSDs that look different from each other but are all in fact SATA-based.

Like HDDs (Hard Disk Drives), 2.5-inch SSDs differ in terms of thickness - 7mm and 9.5mm. By adding an adapter or a spacer to it, you can make a 7mm SSD compatible with a 9.5mm one, but you cannot make the latter compatible with the former by doing so. Therefore, the current 2.5-inch SSDs we are able to find in the market are basically all 7mm-thick.
Although 2.5-inch SATA SSDs have a relatively long history, still it does not mean that they are obsolete or out-dated. For example, Toshiba’s TR200 SSD is built on its brand-new 96-layer BiCS4 flash memory, which is even more advanced and sophisticated than the company’s 64-layer BiCS3 flash memory that is used in iPhone. Taking both cost and performance into consideration, I would recommend SATA SSDs to the users whose CPU has no more than 8 threads.

mSATA SSD Interface:
We can easily tell from its name that mSATA SSD (mini SATA SSD) is the smaller version of SATA SSD. Despite its distinctive appearance, it functions in virtually the same way that SATA does and has exactly the same performance as SATA. However, due to its small capacity and the low-density flash memory back then, mSATA soon became unnecessary and obsolete, and it was finally replaced by other products.

mSATA is identical in terms of appearance to another mini PCIe connector, but they are electrically incompatible and not interchangeable, which can be somewhat confusing to some users. Since mSATA SSD interface has already been obsolete, we can add a 2.5-inch SATA SSD to our laptops by putting a hard drive caddy into the optical drive bay.
M.2 Connectors：
Originally known as NGFF (Next Generation Form Factor), formally called M.2, M.2 connectors is now a widely-used specification of small devices. Besides SSDs, it can also be utilized for many other gadgets such as Wi-Fi wireless cards and 4G WWAN card, which depends on its key type. Of course, among all those uses for M.2, SSD remains it most common use.
According to their length, M.2 SSDs come in five form factors, which are included in their product names - 2230, 2242, 2260, 2280, and 22110. The smaller the size is, the more sophisticated and complicated the design has to be. The M.2 2230 SSD is so small that it can but accommodate only one chip.

In terms of protocol, M.2 SSDs can be divided into two types: SATA and NVMe. Yes, our old friend SATA appears again. If you favor MLC NAND flash memory, you can consider Toshiba’s classic SSD Q200 EX M.2 SATA for your laptop computers. But for desktop computers, you may want to consider a better choice of M.2 SSD: Toshiba’s RC100 NVMe SSD.

Generally speaking, M.2 2230 can only be made into small-capacity SATA SSDs due to its extremely small size as a limiting factor. Nevertheless, Toshiba’s BG series changed the situation. Leveraging Toshiba’s ultra-compact BiCS Flash and MCP (Multiple Chip Package) technology , the BG3 series use a small single chip to achieve ultra-speed NVMe storage that reaches up to 512 GB.

In addition, Toshiba managed to offset RC100’s lack of DRAM and inadequacy of performance by utilizing the HMB (Host Memory Buffer) feature in NVMe protocol, which allows the drive to request exclusive access to a small portion of the host system’s DRAM for the drive’s use. The RC100 in the BG series also entered the retail market later on, with its form factor changed into M.2 2242.

M.2 slots can be very changeable, too, which can be tricky sometimes. Although they look just the same, yet they are different in corresponding lanes and each has a unique mechanical key, which are labeled on the motherboard. For example, some M.2 slots can only be either SATA-specific or PCIe-specific. NVMe SSDs can only make sense over the PCIe lanes.

Some relatively old motherboards can only support a speed of data transmission up to 10Gb/s when loaded up with NVMe drives.

On the M.2 slot, there are several places that we can choose to insert the screws according to the size of the M.2 SSD, so that it can fasten and hold M.2 SSD with different sizes in position. Toshiba’s RC100 with M.2 2242 form factor can fit into almost every M.2 slot that uses PCIe lanes, and thus it provides users with performance and versatility that are even greater than those of SATA SSD.

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