AMD’s Radeon HD 5000-series cards are already considerably more power efficient than anything in Nvidia’s Fermi lineup, but PowerColor’s Go Green series of cards are engineered to consume even less electrical power than reference design-cards. This passively cooled Radeon HD 5750 (PowerColor part number AX5750 1GBD5-NS3DH, to be precise) draws all the power it needs from the PCI Express bus, so it doesn’t require a dedicated six-pin power cable. No fan means no noise.The Radeon 5000-series has another major advantage over Fermi cards: They’re capable of streaming uncompressed high-definition audio from Blu-ray discs (Dolby TrueHD and DTS-HD Master Audio) over HDMI. Fermi has the hardware for this, but Nvidia has not yet released a driver that enables it (although we don’t expect that day is far off).