SATA, IDE, and ATA are all interfaces used to connect storage devices like hard disk drives and optical drives to a computer’s motherboard. Understanding the differences between these interfaces is important when buying new drives or upgrading an older computer.
What is SATA?
SATA stands for Serial Advanced Technology Attachment. It is the newest of the three interfaces and provides the fastest data transfer speeds. SATA has mostly replaced IDE and ATA in modern computers.
Here are some key things to know about SATA:
- SATA was introduced in 2001 as the successor to the older Parallel ATA (PATA) interface.
- SATA uses serial signaling instead of parallel signaling, which allows for higher transfer speeds, thinner cables, and reduced cable clutter inside a PC.
- The latest SATA revision is SATA 3.0 which provides transfer speeds up to 6 Gb/s (gigabits per second). Older revisions SATA 1.0 and SATA 2.0 supported 1.5 Gb/s and 3 Gb/s respectively.
- A SATA cable has seven pins and connects to a matching SATA port on the motherboard or controller card.
- SATA devices can be hot-swapped, meaning they can be connected and disconnected without rebooting the system.
- Common SATA storage devices include hard disk drives (HDDs), solid state drives (SSDs), and optical disc drives like Blu-ray and DVD drives.
What is IDE?
IDE stands for Integrated Drive Electronics. It was the primary interface used for storage devices in older computer systems before being replaced by SATA.
Here are some key things to know about IDE:
- IDE was introduced in the mid-1980s as an improvement over earlier interfaces like ST-506 and ESDI.
- IDE uses parallel signaling to transmit data to connected drives. This allows for simple cabling but limits transfer speeds compared to serial interfaces like SATA.
- The fastest IDE version is Ultra DMA Mode 7 which supports up to 133 MB/s transfer speeds.
- An IDE cable is wide, flat ribbon cable with 40 or 80 wires and large connectors. IDE cables must be connected correctly to avoid damage.
- IDE channels support two separate drives per channel, referred to as master and slave drives.
- Common IDE devices include hard drives, CD/DVD-ROM and CD/DVD-RW optical drives.
What is PATA/ATA?
PATA stands for Parallel Advanced Technology Attachment. It is also referred to as just ATA.
Here are some key things to know about PATA/ATA:
- ATA was the first interface created for connecting storage devices to PCs, introduced in the 1980s.
- Over time the interface evolved from basic ATA to Enhanced IDE (EIDE) to Ultra ATA before finally being renamed to PATA.
- All versions use parallel signaling to transmit data and a wide flat ribbon cable to connect drives.
- Maximum transfer speed increased over time from 10 MB/s on early ATA to 133 MB/s on the final PATA version.
- ATA originally could support up to two drives per channel but later versions increased this to four drives.
- Common PATA drives include HDDs, CD-ROMs, CD-RW, DVD-ROM, DVD-RW, and Zip drives.
SATA vs IDE/PATA
When comparing SATA and IDE/PATA, there are several key differences:
| Feature | SATA | IDE/PATA |
| Interface Type | Serial | Parallel |
| Speed | 1.5 – 6 Gb/s | 10 – 133 MB/s |
| Connector size | Small, 7 pins | Large, 40-80 pins |
| Cable size | Thin serial cable | Wide ribbon cable |
| Hot swappable | Yes | No |
| Drives per channel | 1 drive | 1-2 drives |
In summary, SATA is newer, faster, uses thinner cables and supports hot swapping. IDE/PATA is older technology with larger connectors and cables but allows two drives per channel.
SATA Generations
There have been several generations of SATA interfaces over time with improving performance:
- SATA 1.0 – First SATA version released in 2001, providing 1.5 Gb/s speeds.
- SATA 2.0 – Released in 2004, doubled speed to 3 Gb/s.
- SATA 3.0 – Released in 2009, increased speed to 6 Gb/s.
- SATA 3.1 – Minor revision in 2011, added support for mSATA.
- SATA 3.2 – Released in 2013, added support for M.2 drives.
- SATA 3.3 – Unified branding for SATA Express in 2016.
- SATA 3.4 – Newest SATA version released in 2017, includes new low power modes.
The maximum speed has steadily doubled with each major SATA generation. Most modern storage devices like SSDs can take advantage of SATA 3.0 speeds, while hard drives are limited to around 1.5 Gb/s.
IDE/PATA Revisions
IDE/PATA also went through several revisions before being replaced by SATA, each with improved performance:
- ATA-1 – The original ATA spec released in the 1980s, provided 10 MB/s speeds.
- ATA-2 – Improved speeds up to 16 MB/s in the 1990s.
- ATA-3 – Introduced SMART drive monitoring capabilities.
- Ultra ATA – First version to go beyond 16-bit, doubled speed to 33 MB/s.
- ATA/33 – Minor speed boost to 33 MB/s.
- ATA/66 – Doubled Ultra ATA speed to 66 MB/s.
- ATA/100 – Increased speed to 100 MB/s.
- ATA/133 – Final PATA version, providing 133 MB/s transfer speeds.
Each version gradually ramped up the maximum bandwidth possible over the parallel ATA interface. But the speeds quickly became limited compared to advancing serial interfaces.
SATA vs IDE/PATA Connectors
SATA and IDE/PATA use very different types of physical connectors to connect drives to the computer:
- SATA connectors are small L-shaped ports with seven metal pins. They provide a secure but removable connection to lock SATA drives in place.
- IDE connectors are large, wide connectors that require pressing levers to fix an IDE drive into place. They were designed for easy insertion without worrying about orientation.
The different SATA and IDE connectors reflect the capabilities of each interface. SATA supports removable hot swap drives and needs a more complex connector. IDE was designed for simpler internal drive connections.
SATA vs IDE Cables
The cables used to connect drives for each interface are also quite different:
- SATA cables are thin, 7-pin serial cables that can be up to 1 meter long. Multiple SATA devices daisy chain off each cable.
- IDE cables are wide 40 or 80 wire parallel cables. They must be correctly oriented to avoid damage. IDE cables have a max length of only 45 cm.
Again, the SATA cable design reflects its support for fast external devices, swapping drives, and serial signaling. IDE cables were simpler but required care when handling due to the parallel wires.
SATA vs IDE Drives
While SATA is designed as the successor to IDE, there is still some crossover in terms of compatible drive types due to the transition between interfaces:
- Most 3.5 inch hard disk drives can support both IDE and SATA connections with the right cables.
- 2.5 inch notebook hard drives are typically SATA only.
- SSDs use SATA almost exclusively, with some older IDE SSDs.
- Optical drives like DVD or Blu-ray drives can have either SATA or IDE connections.
When shopping for new drives, SATA is now the default standard across HDDs, SSDs, and optical drives. But some older IDE drives can work via SATA with adapters. External enclosures handle the conversions internally.
Mixing SATA and IDE Drives
Can you connect both SATA and IDE drives in the same system? It is possible with a few considerations:
- Motherboards will typically support either SATA or IDE connectors, not both.
- Adapter cards can be installed to add SATA ports to an IDE board or vice versa.
- Storage controllers sometimes support both SATA and IDE drive connections.
- Older towers included both IDE and SATA cables for flexibility.
When mixing IDE and SATA drives, pay attention to having both the correct connectors and device drivers. The drive modes can usually be changed in the BIOS as needed.
Converting IDE to SATA
With SATA as the new standard, you may need to convert IDE drives or connections to SATA. Here are a few ways to convert:
- Use adapter cables that convert IDE to SATA connectors.
- Install a controller card that adds SATA ports.
- Connect old IDE drives to a newer PC via an external USB enclosure.
- Directly replace an IDE drive like a hard disk or DVD drive with a new SATA model.
When converting physical connections, pay attention to master/slave/cable select drive configurations. The BIOS may need drive mode adjustments.
SATA vs IDE Performance
The key performance difference between SATA and IDE comes down to drive bandwidth:
- SATA provides much higher maximum drive bandwidth, starting at 1.5 Gbps and going up to 6 Gbps for SATA 3.0.
- The fastest IDE speeds reached only 133 MB/s.
In real-world usage, a SATA 3.0 HDD can transfer data around 600 MB/s while high RPM IDE HDDs topped out around 100 MB/s. SSDs can take full advantage of SATA 3.0 bandwidth up to about 550 MB/s.
The speed advantage of SATA allows it to keep pace with modern high speed SSDs, hard drives with dense platters, and multi-TB storage needs. IDE/PATA fell behind as drive technology outpaced interface speeds.
Other Differences
Here are some other differences between the SATA and IDE/PATA interfaces:
- SATA handles reading and writing data separately using full duplex communication over two pairs of conductors. IDE uses one pair for both directions.
- SATA supports spread spectrum clocking for reduced EMI interference. IDE has greater electromagnetic interference.
- SATA has a lower pin count and reduced cable size that improves airflow and heat levels inside a PC case compared to IDE ribbon cables.
- Advanced SATA features like hot swapping require special operating system support. IDE drives are simply plugged-in.
- SATA connectors and ports are keyed to prevent incorrect insertion. IDE relied on the cables to be plugged in correctly.
In general, SATA introduced more modern communication standards like increased transmission speeds, full-duplex transmissions, and advanced protocol features compared to the earlier IDE technology.
Conclusion
SATA has replaced IDE as the interface of choice for connecting storage drives to a computer. SATA offers faster data speeds, thinner cables, smaller connectors, reduced electromagnetic interference, and support for modern SSDs and high capacity hard drives.
IDE and PATA are now outdated legacy interfaces that cannot keep pace with faster modern drive technologies. Occasional IDE usage remains for older optical drives or adapting older hard drives to newer PCs.
When purchasing new storage drives or upgrading a computer, SATA 3.0 provides the best performance. Both hard drives and SSDs can take advantage of SATA 3.0’s 6 Gb/s bandwidth.
Understanding the SATA generations and knowing the differences between SATA and IDE connections will ensure you get optimal storage speeds and compatibility when assembling or upgrading a PC.
