No, you cannot use the Seasonic 12VHPWR adapter cable in the reverse configuration you described. Here’s why:

- The 12VHPWR connector is designed to be connected to the power supply unit (PSU) that supports the new ATX 3.0 or PCIe 5.0 specifications, and the 8-pin connectors are meant to be connected to the graphics card (GPU).
- Using the cable in reverse would not only be incompatible with the intended design but also potentially unsafe, as it could lead to improper power delivery and damage to the components.

The correct configuration is to connect the 12VHPWR end to the PSU and the dual 8-pin ends to the GPU. This ensures proper power delivery and safety according to the manufacturer's specifications.