Regarding cabling from a standard PC power supply.
The blades draw up to 10A at 12V. A single yellow or black cable simply is too small diameter to carry the current so it gets hot ( in the same way as an electric fire element glows red). The cure is to double up the feeds into each terminal post and to remove any connectors.
In my case I have an 1100W PSU. I went through all the feedout cables and stripped off all the end connectors, separated all the yellow (+12V) and black (ground/0V) ones. I cut all the others off inside the PSU and added the green wire to ground link inside the psu case as well.
I then used 4 x yellow and 4 x black wires for each blade - simply twisting two together to put in each hole.
All cabling runs COLD at 1.20V/overclocked 13GH's per blade.
Not pretty but works fine!