IDE and PATA Ribbon Cables

40 pins for desktop drives, 44 for laptop drives

Desktop 3.5-inch hard drives and optical drives use a 40-pin connector and take power through a separate four-pin Molex plug. Laptop 2.5-inch drives use a smaller 44-pin connector that carries power in the same plug, and converter cables bridge the two sizes. Cable quality matters for speed: an 80-wire ribbon, which still ends in 40 pins, is required for the faster UDMA modes from 66 up to 133, while a 40-wire ribbon limits the drive to UDMA 33. Pin 1, marked by the red stripe, normally sits next to the power connector on the drive.

What the three connectors on the ribbon are for

An IDE channel holds two devices. On an 80-wire cable the connectors are color-coded: blue goes to the motherboard, black at the far end to the primary (master) drive, and gray in the middle to the secondary (slave) one, with the drive jumpers set to cable select or to master and slave to match. Many modern boards lack an IDE socket altogether, and bridge adapters between IDE and SATA work only in the direction they were built for. The listing also mixes in SATA, eSATA and network cables, so confirm the IDE type and the pin count in the title.

Questions about IDE and PATA Ribbon Cables

Can I connect a SATA drive to an IDE cable?

Not directly. SATA and IDE use different signals, so you need a bridge adapter with a conversion chip. Pick the right direction: one type puts a SATA drive on an IDE port, another puts an IDE drive on a SATA port.

Is there a right way round for an IDE ribbon cable?

Yes. The red or colored stripe marks pin 1, which goes next to the power connector on the drive and to pin 1 on the motherboard socket. Many connectors have a key notch that prevents reversing, but not all do.

Why does my IDE drive run slowly?

A 40-wire cable limits a drive to UDMA 33, so an 80-wire cable is needed for the higher modes. Also check that the drive is jumpered correctly and that both the drive and the controller support the faster mode.