How AMD's Fusion A8-3850 APU Changes Personal Computing

Power consumption

Looking at power consumption can be done in many different fashions. Historically most reviewers simply provided figures for idle and load power consumption. Load power consumption is sometimes divided between CPU, GPU and combined power draw. Load is usually generated using special programs that strain the respective hardware subsystems to its very limits, which means temperatures and power consumption is maximized.

We consider this approach as valid and will provide the results of our measurements. CPU load was generated using Prime, while GPU load was generated using MSI Kombustor.

As you can see the majority of the power budget is allocated for the CPU cores. This somewhat contradicts the design approach AMD outlined, though that refers to silicon space and not actual power consumption. Still it's something to take into consideration.

However we'd like to point out, that while this correctly shows what is going on at minimum/maximum workloads, it doesn't reflect power consumption in practice at all. Back at E3 AMD put up an interesting slide explaining that in a quad-core CPU, depending on the workload, all four cores are rarely used at once. According to the figures from AMD, even when you are doing video editing, no more than two cores are utilized over half of the time.

While one could debate about these very figures, the essence to take away is, that often less than four cores are utilized and might not be loaded to 100%. AMD used it to explain how the turbo feature comes in handy. We use it here to make a point towards real world power use. Since not all cores are usually loaded to the max, the power figures are much lower for practical workloads.

Therefore, we will informally give a few additional power figures, to give you an overview on how Llano fares when used for various tasks. When browsing the web, the computer is usually not strained to it's limits. Even when using lots of tabs and watching 1080p videos on YouTube, Llano not only performs well, it does so with only 75W-90W of power draw. When playing actual games like World of Warcraft or Dirt 3, power consumption is in the 130W to 150W range.