Molex to pcie cable mod. No fires yet!!
A good molex to PCI-E can take up to 12 amps before even turning "hot"
With 8 pin most load is distributed so that every cable gets approx 2 to 4 amps. Nothing to worry about.
Such connectors over time only get worse if you plug 'm in, plug 'm out, for approx 25 times. Corrosion occurs with that.