We found a SilverStone SST-ST45SF-G 450W SFX12V SLI Ready CrossFire Ready 80 PLUS GOLD Certified Full Modular Active PFC Power Supply in our Steam Machine.

Some notable features about the power supply:

450 W continuous power output at 40° C operating temperature rated for 24/7 operation

80 PLUS Gold level efficiency (87%~90% efficiency at 20%~100% loading)

Silent running 80 mm fan with 18 dBA minimum