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).
PowerColor's engineers acheived a 21-percent reduction in power consumption compred to a reference-design Radeon HD 5750
But if you’re thinking this and the passive cooling render this particular 5750 the perfect solution for that home-theater rig you’re building, fuhgeddaboutit: The oversized dual-slot heatsink extends far beyond the edge of the PCB. When we installed it in our home-theater PC—an AMD reference design in itself—the card’s top edge stood a full inch above the enclosure’s mounting bracket (the machine is housed in an nMediaPC HTPC 1000 enclosure).
But to be fair to PowerColor, they’re not marketing this card as a home-theater solution. And if you’re just looking for a Blu-ray player, a 5750 paired with a 1GB frame buffer is more than you need anyway. Evaluate the Go Green 5750 as a mid-range gaming card, however, and you’ll see that it’s considerably more expensive than competing cards equipped with conventional heatsinks and fans—in fact, it’s about the same price as conventionally cooled cards based on the more powerful Radeon 5770.
As you can see from the benchmark charts, the Go Green 5750's heatsink does a remarkably good job of keeping the GPU cool. Copper heat pipes wick heat to the fins on the large passive radiator, where it's dissipated into the rest of the case. When we installed the card in a conventional mid-tower enclosure and played Just Cause 2, the GPU's sensors never registered a temperature higher than 74.5 C. And when we moved the card into our home-theater PC and played a Blu-ray movie, GPU temps never moved above 66 C (although we put the lid on the case, we couldn't close it entirely because the card is too tall).
Economically speaking, you’ll likely never save enough on your energy bill to recoup the difference between the cost of a Go Green 5750 and the cost of a more conventional card based on the same GPU. Environmentally speaking, on the other hand, you will be reducing your carbon footprint—and it’s hard to put a price on that.