MSI announced one of their GreeenPower design motherboards reached a FSB of 669MHz:
MSI has reached extreme high Overclock results with the MSI X48 Platinum of 669Mhz FSB! This because the MSI X48 series is equipped with the MSI GreenPower PWM Design (PWM: Pulse Width Modulation). Its advanced design consists out of a dual channel 4-phase PWM. Each channel is build up by 2 shielded chokes (to prevent power leakage) and a MOSFET base which brings the highest power efficiency. This original and revolutionary GreenPower design by MSI leads the motherboard’s power design in fewer phases to provide better power supply.
“This high clocked FSB on our X48 series equipped with MSI GreenPower PWM design proofs that a good 4 phase PWM design is far more effective than most 6, 8 or 12 phase PWM design.” said Eric van Beurden, product manager components. “In the future we will see more 4 Phase PWM designs which require a less powerful PSU because in this case, less is better.”