Which ribbon cable is used by an ATA/133 HDD?

The correct choice is the 40-pin / 80-wire ribbon cable for an ATA/133 hard disk drive (HDD). This type of ribbon cable is specifically designed to support Parallel ATA (PATA) devices and is an enhancement over the older 40-pin / 40-wire cables.

The 80 wires in this cable provide better data transfer rates by allowing for more efficient transmission of data, helping to minimize interference and crosstalk between the wires, which is particularly important for higher-speed standards like ATA/133. The extra wires do not add additional data lanes but rather provide additional ground connections which enhance signal quality.

In contrast, options such as the 20-pin / 40-wire do not support standard HDD interfaces like ATA/133, while the 40-pin / 40-wire lacks the data integrity improvements that the 80-wire option offers for higher-speed operations. The 50-pin option is typically associated with SCSI devices and is not suitable for IDE/PATA applications. Thus, the 40-pin / 80-wire configuration is the correct cable type used with an ATA/133 HDD, enabling it to achieve the performance specifications associated with that standard.