I may have fixed the random shutdown failures by increasing air flow to the computers.

This two-step mating process avoids glitches to other loads and possible arcing or erosion of the SATA power connector contacts. Finally, the remaining power pins make contact, bypassing the resistances and providing a low-impedance source of each voltage. The drive uses them to charge its internal bypass capacitors through current-limiting resistances. Drive power connector pins 3, 7, and 13 are longer than the others, so they make contact next. Ground pins 4 and 12 in a hot-swap cable are the longest, so they make contact first when the connectors are mated.

Two ground pins, and one pin for each supplied voltage, support hot-plug precharging.

Five parallel pins provide a low-impedance ground connection.

To reduce impedance and increase current capability, each voltage is supplied by three pins in parallel, though one pin in each group is intended for precharging (see below).

However, very few drives actually use it, so they may be powered from an old 4-pin Molex connector with an adapter.

3.3 V is supplied along with the traditional 5 V and 12 V supplies.

The new SATA power connector contains many more pins for several reasons: Some early SATA drives included the old 4-pin Molex power connector together with the new 15-pin connector, but most SATA drives now have only the latter. It is a wafer-type connector, like the SATA data connector, but much wider (15 pins versus seven) to avoid confusion between the two. SATA specifies a different power connector than the decades-old four-pin Molex connector used on Parallel ATA (PATA) devices.

A 15-pin SATA power connector this particular connector is missing the 3.3 V (orange) wire.

Apple mac pro 2012 powersupply