The Serial ATA (SATA) port on a solid state drive (SSD) is the interface that allows the SSD to connect to the computer’s motherboard and transfer data. SATA has become the standard interface for SSDs and hard disk drives in desktop and laptop computers over the past couple decades, replacing the older Parallel ATA (PATA) interface.
Introduction to Serial ATA
Serial ATA or SATA is a computer bus interface that connects host bus adapters to mass storage devices such as hard disk drives, solid-state drives, and optical disc drives. SATA was designed to replace the older Parallel ATA (PATA) standard, offering several advantages over its predecessor:
- Faster transfer speeds – First introduced in 2003, SATA initially offered transfer rates of 1.5 Gbit/s. Subsequent revisions have increased speed to 3 Gbit/s (SATA II), 6 Gbit/s (SATA III), and up to 16 Gbit/s (SATA Express). This enables faster data access from storage devices.
- Thinner cables – SATA cables are much thinner and more flexible than PATA ribbons cables, improving case airflow and ease of installation.
- Simplified cabling – One cable connects a SATA device to the controller instead of two separate cables for data and power. Most SATA devices don’t require jumper configuration like PATA.
- Software control – Advanced SATA features are configured through software rather than jumpers on the drive itself.
- Native hot swapping – SATA supports hot swapping, allowing drives to be connected and removed without rebooting the system.
The SATA standard is maintained by the Serial ATA International Organization (SATA-IO). Various revisions of the SATA specification have been released over the years:
SATA Revisions
| Version | Year Introduced | Speed |
|---|---|---|
| SATA 1.0 | 2003 | 1.5 Gbit/s |
| SATA 2.0 | 2004 | 3 Gbit/s |
| SATA 3.0 | 2009 | 6 Gbit/s |
| SATA 3.2 | 2013 | 16 Gbit/s |
The latest SATA 3.3 specification was released in 2016, focused on optimizations like new power management and improved queued commands. SATA remains the most common storage interface in desktop PCs and laptops today.
SATA SSD Interface
Solid state drives connect to a computer’s motherboard using the Serial ATA interface. Some key points about SATA and SSDs:
- Most consumer SSDs today utilize the SATA III interface, providing up to 6 Gbit/s transfer speeds.
- SATA is a point-to-point interface, allowing just one device per SATA port.
- 2.5-inch SSD form factors match traditional HDD dimensions and interface via SATA ports.
- M.2 SSDs may use SATA or PCIe interfaces, depending on the specific M.2 implementation.
- To achieve full SATA 6Gbps throughput requires quality cables, controllers, and SSDs.
SATA Port Connectors
There are several SATA connector types that may be present on a computer motherboard or SSD:
| Connector | Description |
|---|---|
| SATA | Standard 7-pin SATA connector for data transmission to storage drives |
| SATA Power | 15-pin connector that provides power to SATA devices |
| mSATA | Mini SATA connector for smaller form factor SSDs |
| M.2 SATA | M.2 slot interface compatible with SATA-based M.2 SSDs |
The SATA data connector clicks into place on 2.5-inch SSDs and hard drives. SATAPower15 connectors may be required on some drives to provide adequate power delivery for operation.
Benefits of SATA for SSDs
While newer interfaces like PCIe and NVMe are increasing in popularity, SATA continues to be the predominant interface for SSDs due to several benefits:
- Ubiquity – SATA ports are standard on all modern motherboards and widely supported.
- Cost-effective – SATA controllers and SSDs tend to be affordable compared to higher-end PCIe options.
- Proven reliability – SATA is a mature, time-tested interface.
- Good speeds – SATA III provides up to 6 Gbps bandwidth, saturating the capabilities of many non-PCIe SSDs.
- Easy installation – SATA connections just click into place; no driver or BIOS configuration needed.
For budget builds and basic computing needs, SATA SSDs deliver excellent performance and value. Power users with cutting-edge PCIe 4.0 SSDs can still benefit from having SATA SSDs or HDDs as extra storage drives.
Differences Between SATA, PCIe, and NVMe SSDs
Under the hood, SATA, PCIe, and NVMe SSDs store and access data using similar NAND flash memory chips. The main differences come down to the interface and protocol:
SATA
- Uses the SATA III interface, providing up to 6 Gbps bandwidth.
- Compatibility with the AHCI command protocol used by hard disk drives.
- Typically maxes out around 550 MB/s sequential read/write speeds in real-world usage.
PCIe
- Utilizes direct connection to PCI Express on the motherboard instead of SATA.
- PCIe 3.0 x4 allows up to 4GB/s bandwidth, PCIe 4.0 x4 up to 8GB/s.
- Still uses the AHCI command protocol like SATA SSDs.
- Capable of sequential reads/writes over 3,000 MB/s on PCIe 3.0 or over 5,000 MB/s on PCIe 4.0.
NVMe
- Uses PCIe interface like PCIe SSDs.
- Improved performance from NVMe command protocol optimized for non-volatile memory.
- Low latency and high input/output operations per second (IOPS).
- Top bandwidth over 3,500 MB/s on PCIe 3.0 and 7,000 MB/s on PCIe 4.0.
In summary, NVMe SSDs connected via PCIe deliver the fastest speeds thanks to PCIe bandwidth and an optimized command protocol. But for more affordable builds, SATA SSDs still provide huge improvements over hard disk drives.
SATA SSD Speed Considerations
Several factors affect the real-world speed of a SATA SSD:
- Drive specs – Faster SATA drives boast higher sequential and 4K random read/write speeds.
- Controller – The SSD controller manages traffic between the flash memory and SATA bus.
- Flash memory – Higher quality 3D NAND chips improve sustained write performance.
- SATA controller – Older SATA II ports limit speed to 3Gbps regardless of drive capability.
- File transfers – Small files measured in KB/s see much lower speeds than large sequential file copies.
Even high-performance SATA III SSDs may not reach full rated speeds during general consumer workloads. Heavy multitasking and large file transfers will enable the SSD to best demonstrate its capabilities.
SATA SSD Speed Comparison
| SSD | Sequential Read | Sequential Write |
|---|---|---|
| SATA III Budget SSD | 500 MB/s | 450 MB/s |
| High-end SATA III SSD | 550 MB/s | 520 MB/s |
| NVMe PCIe 3.0 SSD | 3,500 MB/s | 2,500 MB/s |
While a high-end SATA SSD may reach 550 MB/s sequential reads, a newer NVMe SSD over PCIe 3.0 delivers over 6x higher bandwidth. But for everyday tasks, most users would not perceive a huge difference between these SATA and PCIe SSDs.
SATA Compatibility with NVMe/PCIe SSDs
When shopping for a new SSD, compatibility is an important consideration. Here are some guidelines regarding SATA, PCIe, and NVMe SSD compatibility:
- NVMe SSDs only work installed directly into a PCIe M.2 or Add-in Card slot with PCIe lanes.
- Most M.2 PCIe SSDs will not function installed into a M.2 SATA slot.
- 2.5-inch SSD form factors with SATA connectors ONLY work with SATA ports.
- Some motherboards support SATA and PCIe M.2 slots, allowing either type of SSD.
- Research your motherboard specs to find available SATA ports and PCIe/M.2 slots.
- Using a SATA SSD requires no driver installation or bios configuration unlike NVMe.
With different connector shapes and bus interfaces, SATA SSDs and NVMe PCIe SSDs are not interchangeable. Choose an SSD that matches the ports and slots available on your motherboard.
Conclusion
The Serial ATA interface plays a crucial role in connecting solid state drives to desktop and laptop PCs. SATA allows SSDs to transfer data to the computer’s motherboard at high speeds up to 6 Gbps. While faster PCIe and NVMe SSDs exist, SATA III remains the most common and cost-effective SSD interface thanks to its ubiquity and good performance.
When purchasing or upgrading an SSD, check for available SATA ports on your motherboard to ensure compatibility. While M.2 and PCIe SSDs receive more attention for bleeding-edge speeds, the SATA III interface continues to serve as the workhorse for modern storage. For a balanced system upgrade, pairing a speedy PCIe or NVMe boot drive with high capacity SATA SSD storage provides lightning responsiveness and ample space for games and media files.