750 Watts Power Supply provides 2x 6 Pin power cables. The Quadro series GPU requires 8 pin and 6 pin power connectors, so a 750 watts power supply will need a 6 to 8 pin conversion adapter. In the sections below, the connection for each variant of GPU is explained.
HP 6 Pin to 8 Pin Power Supply Adapter
For GPUs which require 8 Pins power cables, HP has a certified adapter cable from 6 Pin to 8 Pin. So, this converter should be used with 750 Watts power supply.
Do not use any other brand adapters which have a similar specification. Do not use SATA or Hard disk power cable to 8 pin converters as this may damage your GPU or power supply.