SCSI, PATA, SATA, and NVMe Explained

An interface or cable connects a device to the motherboard. There are many interfaces. Different interfaces use different technologies to carry data between the motherboard and the connected device.

Following are the four types of interfaces that you can use to connect hard disks to motherboards.

  1. Small Computer System Interface (SCSI)
  2. Parallel Advanced Technology Attachment (PATA)
  3. Serial Advanced Technology Attachment (SATA)
  4. NVMe (Non-volatile Memory Express)

Let us understand these interface types in detail.

This tutorial is the last part of the tutorial series "Hard Disk Type, Data Transmission Technology and Interfaces Explained.". Other parts of this series are the following.

Differences between Hard disks and SSDs Explained

Why Do Hard Disks use Serial Transmission?

Small Computer System Interface (SCSI)

SCSI was developed in the mid-70s as a common interface to connect multiple devices to the motherboard. Until the dedicated interfaces to connect devices to the motherboard were not developed, SCSI was used as a default interface to connect scanners, printers, and hard disks to the motherboard.

Initially, it was developed for parallel transmission. Later, it was upgraded for serial transmission as well. Serial SCSIs offer faster data transmission speed than the Parallel SCSIs. It can transfer data up to 80 megabytes/second.

scsi interface

After the development of dedicated interfaces, the use of SCSI interfaces gradually declined. SCSI interfaces are no longer used to connect hard disks to motherboards.

Parallel Advanced Technology Attachment (PATA)

Parallel Advanced Technology Attachment (PATA) is also known as IDE (Integrated Drive Electronics). It was developed as the dedicated interface for the storage devices. It was launched in 1986 and was widely used in computers until the early 2000s. It uses parallel data transmission technology.

ide cable

PATA cables typically had 40 or 80 pins. With a 40-pin cable, you can connect a single storage device to the motherboard. With an 80-pin cable, you can connect two storage devices to the motherboard. It offers a maximum data transfer speed of 133 MBytes/second.

Serial Advanced Technology Attachment (SATA)

SATA was developed as a replacement for PATA. It was launched in 2003. It became popular within a few years of its launch. Within a decade, it captured 98% of the market share in personal computers. It uses serial transmission. Serial transmission reduces processing overhead and crosstalk.

sata cable

It is available in different generations. First-generation SATA was launched as a 1.5 Gbps interface. The latest generation is the third generation. SATA III offers a maximum data transfer rate of 6 Gbps However, its bandwidth is limited, making it less suitable for high-performance applications that need faster data transfer speeds.

Non-Volatile Memory Express (NVMe)

Non-volatile memory Express (NVMe) is explicitly developed for SSD drives. SSD drives are designed for the modern computers. Unlike traditional hard disks that use magnet-coated platters to save data, SSD drives use chips to store data. They provide blazing-fast data transfer speed. They can transfer data at the speed of 32 Gbps. There are two types of SSD: SATA SSD and NVMe SSD.


SATA SSD uses a SATA interface. NVMe SSD uses an NVMe interface. The SATA interface uses a SATA cable to connect the SSD drive to the motherboard. NVMe interfaces are directly mounted on the motherboard. You can call them NVMe slots. You need to attach NVMe SSD disks directly to these slots.

NVMe slots were designed to utilize the full capacity of SSD drives. They work with flash memory using the PCIe (Peripheral Component Interconnect Express) interface. They provide a direct pathway to the CPU, allowing the NVMe SSD to achieve its maximum speeds.

nvme interface or slot

NVMe is a new interface. It is available only on the latest and high-end motherboards. If your motherboard has it, you can use an NVMe SSD drive. If your motherboard does not have it, you can use a SATA SSD or a HDD.


SCSI and PATA interfaces are outdated. They are no longer used in modern computers. Modern computers use only SATA and NVMe interfaces. They use SATA interfaces to connect HDDs or SATA SSDs to the motherboard. To connect NVMe SSD drives to the motherboard, they use NVMe interfaces.

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