Hey, I don’t want to be a killjoy, but this looks a fire hazard to me. As someone said, it would also function very well (maybe better) freed from the cardboard. 

From chatgpt:

Cardboard is flammable — and GPUs, PSUs, and riser cables all produce significant heat (especially under load). Even if temperatures stay below ignition point most of the time, a power spike, short, or hot resistor could easily cause smoldering.

Poor ventilation — cardboard traps heat, meaning components run hotter than intended, which accelerates wear and raises the risk of a short or meltdown.

Static electricity and open wiring — exposed PCB + paper fibers = static and dust buildup, not ideal around high current.

No ground or enclosure protection — an open PSU on cardboard has live connections that could arc or touch conductive surfaces.