The SX650-G and SX500-G both feature an always-on 92mm fan, which will hopefully prove quieter than the 80mm fans in the SX600-G and ST45SF-G. The SX650-G touts an impressive 819W per liter while the SX500-G sits at 630W per liter, both with 80 PLUS Gold-rated efficiency, all Japanese capacitors, and fully modular cables. The OEM is Sirfa/High Power.