This is a gaming PC stuffed inside a standard ATX PSU case.
The mainboard accepts a notebook style 19V power supply, but the GPU needs 12V. So the power supply is a custom solution with an external 12V 350W PSU and an internal DC-DC step up converter to produce the 19V with up to 150W.

The GPU has excellent airflow, as it is basically installed open air; the CPU can breathe enough, so this little G4560 remains in the 60C range under load.
Two Noctua A4x10 fans help the airflow a bit, with the front fan mainly responsible for getting some airflow around the DC-DC converter.

The frontpanel is a placeholder faceplate, that'll be replaced once I get around to fixing my 3D printer.

There's no traditional power button; it has been replaced by the combination of a Screen and a touch sensitive fan grill. :)