It is possible to upcycle an inexpensive / free e-waste XBox 360 power supply into a relatively high-quality mid-capacity power supply.
Positives:
Caveats:
This might vary a bit depending on variant. Hopefully others can add their experiences to this page.
Mark 2M0IIG: When I did this I had four yellow and four black wires rather than three of each. Apparently the thinner wires of each colour are the wires for voltage sensing. If you connect them along with the other three of each colour the PSU will supposedly detect voltage drops and accommodate for it.
Daniel EI8ICB: In some models, the red wire is coloured purple instead. Some models also have a grey wire which should be connected with the black wires - failing to do so will result in the power supply entering an error state once any meaningful current is drawn.