posted by Howard Fosdick on Wed 29th Feb 2012 00:56 UTC
IconCurrent computers use SATA disk drives. Pentium IV's and earlier computers used the IDE drive standards. How can you intermix SATA and IDE disk drives? This article discusses the options. It is the next in my series of articles on computer refurbishing.

People have three basic questions about SATA and IDE disk drives:

  • How can I connect my old IDE drive to a current motherboard having only SATA sockets?
  • How can I connect a SATA drive to an old motherboard having only IDE sockets?
  • How can I best mix IDE and SATA drives in one system?
I'll answer these questions from a practical standpoint for those working with consumer desktops. I omit unnecessary technical details.

What is IDE ?

Hard disks have passed through a long evolution of connectivity and data transfer standards. The drive interface standard from the 1980's was called the IDE (Integrated Drive Electronics) specification. Today it's usually called PATA (Parallel ATA). IDE includes sub-standards with names like EIDE, ATAPI, ATA, ATA-1, ATA-2, UDMA, ATA-4, ATA-133, and more. These sub-standards represent continuing improvement in data transfer speed and reliability

Throughout this evolution, IDE's physical connectors have remained the same. So you could take an old 386 drive from 1988 and plop it into your Pentium 4 from 2005, and it would work! The IDE standards applied across thousands of different drive and motherboard manufacturers.

Here's how the IDE connector sockets on the motherboard look, along with the ribbon cable that goes from the motherboard socket into the back of any IDE drive:

PATA Pictures
PATA Photos (Wikipedia and www.ComputerHope.com)  

The third photo shows a close-up of an IDE drive power plug, the Molex 4-pin plug. It's white and it has a female connector that goes into the 4-pin male connector on the back of the disk drive.

The final photo shows the back of an IDE disk drive. You can see where the IDE data ribbon cable plugs in to connect it to the motherboard and where the Molex power plug goes. Note the jumpers. You can connect either one or two IDE drives to an IDE ribbon cable. You set the jumpers to indicate whether one or two drives on are the same IDE cable, and which drive is where in the sequence. (Connecting SATA disk drives is simpler because they eliminate jumpers.)

Enter SATA

SATA became popular with the introduction of dual core computers five or six years ago. SATA stands for Serial Advanced Technology Attachment. When it came out the IDE standards were retroactively renamed PATA or Parallel ATA to distinguish them from SATA or Serial ATA.

SATA advantages over the older PATA specs include faster data transfer, higher efficiency, hot plugging, reduced cable width, and better internal air flow. Like PATA, the SATA specs have evolved quickly to improve data transfer. SATA's physical connectors for consumer computers have remained the same throughout this evolution.

These photos show the SATA data cable sockets on the motherboard, the red SATA data cable and its end plugs, and the black SATA power plug --

SATA Pictures
SATA Photos (Wikipedia)            


The fourth photo shows the rear of an SATA disk drive. The red SATA data cable is plugged to connect to a SATA motherboard socket to support data transfer. To its right is the SATA power plug. SATA power plugs are by convention black plastic to distinguish them from the white plastic Molex plugs used on the older IDE/PATA drives.

Transitional Hardware

The first step in making PATA and SATA work together is to look at what you have. Most IDE disk drives use an IDE data ribbon connector and a white power plug, while most SATA drives use the SATA data cable connector and a black power plug.

However, you'll sometimes see transition drives. The one below has a SATA data cable connector plug, combined with both kinds of power plug connectors. Label "A" is the SATA power connector, "C" is the "legacy" or IDE power connector, and "B" is the SATA data or "signal" plug. Just use the power plug you have, no worries.


Transitional Drive
Transition Drive Uses Either Power Plug  (Gateway)


Inspect your motherboard, too. Most motherboards have only PATA or SATA data connector sockets. But there are also transition motherboards that have SATA sockets and one or two PATA sockets. Behaviors of boards with both PATA and SATA sockets depend on the motherboard firmware and BIOS. Read your doc to see how your board works. Or just test the configuration you want. Be sure to follow any instructions about the jumpers on the IDE drives.

Many transition motherboards manage PATA and SATA drives together just fine. But there are exceptions. Sometimes you'll find that the drive ordering is hardwired, or that you can't boot from one drive. Inspect the BIOS configuration panels to see if you can change settings to get the behavior you want.

Boards with mulitple SATA connectors and a single PATA connector are still around. They use SATA for their hard disk(s), and the single IDE socket to connect a legacy DVD/CD drive (using the IDE ATAPI optical drive standard). The industry made the switch from PATA to SATA a bit later with optical drives than hard disks.

If you have a motherboard like this, you can use the extra plug on the IDE ribbon cable to add one IDE hard disk to the system. Set the jumpers so that the hard drive is the first or primary drive on the ribbon and the DVD/CD is the secondary or slave drive. This is an easy way to add an IDE drive to a motherboard with a single IDE motherboard socket.

With PATA you didn't normally mix hard and optical drives on the same IDE cable because it can slow data access times. How much degradation you experience depends on the patterns of your disk use and which IDE standards are involved. (I exclude these complexities here.) For typical office work this configuration works fine.

Compatibility Hardware

If your drives and motherboard don't give you compatibility, there's a wide range of hardware products out there to address your needs. Just search on "IDE to SATA" at Amazon. Many products just cost a few dollars. Unfortunately some are flimsy or have poor quality control. You'll also run into occasional compatibility problems if you don't do your homework. Read the product specs and user reviews at Amazon, Tom's Hardware, or Tiger Direct to verify functionality, compatibility, and quality before you buy.

Simple white-plug / black-plug converters can solve your power plug compatibility issues:

Converter Plugs
Compatibility Plugs (Wikipedia)

One drive integration technique uses your computer's USB port to connect an incompatible disk drive. The drive can be a SATA or PATA hard disk drive (2.5" or 3.5"), or it could be any kind of optical drive, such as a SATA DVD or legacy CD drive. This picture shows the pieces in  Eforcity's PATA and SATA Converter Set:

Eforcity USB Set
Eforcity's USB Connector Set (Eforcity and Amazon)


You use your computers' USB port as the interface to connect your incompatible disk drive. Just take whichever tools you need from the toolset to USB-connect your drive and power it. (The toolset does not include a drive enclosure, so you'll want to buy that separately if you use this on a permanent basis.) I've used the product as a quick temporary setup for easy data transfer across incompatible systems. Just connect and copy over your data.

How about permanently mounting an incompatible internal disk drive? This is where you want to put an IDE drive into a SATA-only motherboard or vice versa. I've used Syba's IDE/SATA Converter. This product gives you a wide black plastic connector you plug onto the rear of your hard drive. You set a switch on back of this connector to indicate whether you are going from IDE to SATA, or from SATA to IDE. Then you connect its special power plug that powers both the connector and drive. When the computer boots it includes the converted drive in a transparent manner.

Syba Connectors
Back and Front of Syba's Drive Connector

Syba Converter
Special Power Plug & SATA Data Cable   (Syba and Amazon)


Since the black connector attaches directly to the end of your disk drive, you need to have the inch or two of extra space to mount it. On rare occasions you'll run into a system with the drives packed so tightly they lack sufficient clearance.

I'm using the Syba product right now on a two-year-old HP Pavilion that has only SATA sockets on the motherboard. Two hard drives are connected: a 1 TB SATA disk and a legacy 160 Gig IDE drive connected with Syba. This configuration works well and though the access speed is slower for the IDE drive, I've never noticed it.

Another alternative is to buy an adapter card that plugs into the motherboard and has the sockets you need. The example I/O controller card below gives you one SATA socket, one PATA socket, and one eSATA (external SATA) socket. It supports various disk configuration options (RAID, JBOD) with Windows 7 for only about $20 US --

Controller Card
Masscool SATA & IDE PCI Express Card   (Masscool)


You typically install software drivers for I/O controller cards. Be sure the driver supports your operating system and its version level before purchase. Drive dongles like the Syba do not require device drivers. I use them to avoid driver compatibility issues because I run Linux.

This chart summarizes the three drive integration solutions I've described:


USB Toolset:
Drive Dongle:
Controller Card:




Mounts Drive(s):
External
Internal
Internal & External *
Requires Software Driver:
No
No
Yes
Supports Multiple Drives Simultaneously:
No
No
Yes
Special Requirements:
USB port.
Drive enclosure for permanent use.
Space to attach dongle.
Motherboard card slot. Software driver.
* Controller cards usually have a eSATA or USB port that allows external mounting.

Learn More

I've focused on readability so I've left out some technical details. To learn more, read the Wikipedia entries on PATA, SATA, and disk storage. Should you decide to purchase any compatibility hardware, be sure to read product descriptions and user reviews before buying.

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Howard Fosdick (President, FCI) is an independent consultant who supports databases and operating systems. His hobby is refurbishing computers as a form of social work and environmental contribution. Read his other articles here
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