We'd like to cover a few final data points before bringing this article to a close. Throughout all of our benchmarking and testing, we monitored how much power our test systems were consuming using a power meter. Our goal was to give you an idea as to how much power each configuration used while idling and under a heavy workload. Please keep in mind that we were testing total system power consumption at the outlet here, not just the power being drawn by the motherboards alone.
Using a 40nm process to manufacture the Radeon HD 4770 seems to have really paid off in regard to its power consumption characteristics, at least when the card is running at its reference specifications. In our power consumptions tests, the new Radeon HD 4770 consumed the least amount of power at both idle and under load. What's most impressive is the comparison between the 4850 and 4770--although both cards offer somewhat similar performance depending on the game / settings being used, the Radeon HD 4770 consumes significantly less power under load.
With power consumption this low, it should come as no surprise that the Radeon HD 4770 is a fairly quiet card to operate. Under idle conditions, the Radeon HD 4770 is inaudible over the noise produced by the average CPU cooler and PSU. And under load, the card's fan barely spins up at all. We did have one strange occurrence during our 3DMark Vantage testing where the Radeon HD 4770's fan spun up to full speed and was quite loud, but it happened only once, lasted for only a moment and never happened again.