If you want to use two ATX power supplies then you can purchase an inexpensive ATX Starter device. It will control a 2nd ATX PSU whenever you switch your computer on.
An 80 Watt peltier is no good for CPU cooling.
I have tutorials on my website and also offer free help/support to new peltier users.
Just in case you don't know which wires are which on a Molex connector: The yellow is +12v.
If you're going to wire a pelt via a molex plug then one plug isn't sufficient (for pelts above approx 14 amp consumption). You would need to add two plugs to the peltier device. Otherwise the molex plug will heat up and cause power-loss to the whole system as well as present a fire-hazard.
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