The regulator should not be needed since youre feeding the board 3.3v externally. The regulator is only used when you power the board with 5V such as USB, but want it to run at 3.3v.
Teensy 3.3V regulator cannot power the NANDs on the PS3. The drain of the motherboard summed by the other peripherals draw too much current (~1.8A). The NANDs can be powered from external 3.3V power supply like ATX power supply (the orange 3.3V line of the ATX main connector).