This post was most recently updated on June 15th, 2018
What interface is better for SSDs? Answering this question is complicated and frustrating. However, in order for everyone to be confident when choosing an interface, the storage geek decided to take a serious look at how to choose a solid state hard disk interface.
How to choose a solid state hard disk interface: the types
The SSDs on the market are simply four interface types: SATA, PCIE, M.2, and U.2. Specific to the agreement, it can be divided into upper layer protocols and transmission protocols. The intricate and complicated relationship between them can be expressed in the following figure. It does not matter if you do not understand it now. This article is a detailed interpretation of this figure and strives to make everyone understand the relationship.
How to choose a solid state hard disk interface
How to choose a solid state hard disk interface: SATA interface
Usually referred to as the SATA interface. It is around 2.5-inch in size. it uses only the AHCI protocol, the maximum queue depth is QD32. Also, there is no bottleneck for home. The SATA3.0 interface limits continuous read and writes speeds to around 550MB/s.
The 2.5-inch value is not the diagonal length of the hard disk as many people think, but the diameter of the hard disk inside the mechanical hard disk. In the era of SSDs, flash chips replaced disks as storage media. Without the disc diameter, the SSD is still manufactured in accordance with the original 2.5-inch standard, so that it can be compatible with a variety of desktop and notebook computer hard drives.
HDD Vs SSD Interface
So far, the SATA interface (specifically, the 2.5-inch specification) SSD is still the first choice for upgrading an old computer. The main control scheme of SATA SSDs is relatively mature, and the key factor determining the quality lies in the quality of flash memory. Although many seemingly regular brands of SSDs are also very cheap. However, if you understand the current chip renewal fraud, it will be difficult for them to be convincing.
How to choose a solid state hard disk interface: PCI-E SSD
Strictly speaking, this type should be called AIC (expandable card) solid-state hard drive, but because most people are used to the name PCIE solid-state hard drive. storage geeks here to take care of everyone’s habits. In brief, PCIe SSDs look similar to graphics cards, but in recent years, AIC SSDs have mostly come from SSDs with M.2 interfaces. Some of them will also increase heat sinks.
The PCIE interface is an all-purpose communication interface. It can not only be used to connect graphics cards. Various devices in the computer, such as sound cards and network cards, communicate with the CPU through PCIE. Its status is equivalent to USB, carrying intelligent transmission. However, the specific function is not defined by the PCIE. Therefore, PCIE interface SSDs (using the AHCI protocol) cannot be directly used as system disks to boot Windows. Also, SSDs using NVMe’s upper layer protocol also require special support from the motherboard to be recognized as a hard disk during boot.
How to choose a solid state hard disk interface: M.2 SSD interface
M.2 is the most complex and most variable SSD interface at present. It is a multi-function interface like the mSATA that has been eliminated currently. Under the same appearance, it can support different pin definitions (transport protocols) and different upper layer protocols. The earliest M.2 SSDs used the same SATA AHCI protocol as the 2.5-inch SSDs. In addition to their different appearances, they have basically no difference in performance from the 2.5-inch SATA versions. The typical example is the Toshiba Q200 240G M.2.
The SATA protocol M.2 SSD has two gaps at the interface. The scientific names are B Key and M Key. Their existence is to indicate their identity to the computer host (choose the protocol to be used).
A SATA-notched M.2 SSD can usually be used with the NVMe protocol. However, the two gaps cannot be used as the basis for determining the SATA protocol, because the two gaps can also support the PCIE transmission protocol, which can also be an NVMe solid state drive. There is just such an example recently – Toshiba RC100 just listed.
The U.2 interface is currently mainly used in the server area, and its influence on home computers can be basically ignored. Then the final question is: After understanding the knowledge of these interfaces and protocols, what should the SSD choose?
From the perspective of performance, in fact, we only need to consider the upper layer protocol used by the SSD to have a general understanding of its performance range: NVMe SSD is a high-performance product (needs new computer support), AHCI SSD is an old computer upgrade The right person (compatibility is very good).
How to choose a solid state hard disk interface: Final note
From the installation and use, we need to exclude the physical interface specifications that our computers cannot support. For example, if there is no M.2 interface on the old motherboard, M.2 SSDs cannot be directly installed. At this time, if the NVMe protocol is used, you can consider the riser card (requires the motherboard to support booting and CPU PCIE channel splitting). If it is SATA The M.2 of the agreement is not as good as buying an ordinary 2.5-inch model directly. It is not only cheaper but also has no difference in performance.
Although there are many interface protocols, most people choose 2.5-inch SATA and M.2 NVMe. Storage geek advises the old computer to upgrade the user’s preferred 2.5-inch SATA; already has a SATA solid-state drive that needs to be upgraded, or a new high-performance M.2 NVMe SSD is the preferred choice for newer machines.