Advanced Micro Devices said today that its latest family of processors is 46 percent more energy-efficient in terms of its carbon footprint than the previous generation of chips.

In 2014, AMD set its 25X20 energy efficiency goal to deliver at least 25 times more energy efficiency from its mobile accelerated processing units (APUs, or chips which combine a microprocessor and graphics on the same piece of silicon) by 2020.

This year, AMD launched its new AMD A-series APU (code-named Carrizo). The energy efficiency of the Carrizo processor puts AMD ahead of the trend line needed to achieve the 25×20 goal.

Compared to the previous Kaveri generation of APUs, the Carrizo chips have a much smaller carbon footprint because the chip is more power-efficient and computers that use it burn less energy compared to previous generations, based on a study released today by AMD.

Sam Naffziger, AMD corporate fellow, said in a paper that the emphasis in past years has been on increasing the performance of chips by taking advantage of Moore’s Law, or the doubling of the number of transistors every two years, or so. But as performance increases, so does power consumption. In recent years, both Intel and AMD have put more emphasis on energy efficiency, rather than just raw speed. An observation known as Koomey’s Law holds that the amount of computation that can be done per unit of energy has doubled every 18 months.

The miniaturization of transistors helps reduce power consumption in some respects, but the ability to do that is now bumping into limits imposed by the laws of physics. AMD is trying to come up with design tricks that help get around this problem, and Carrizo is one result.

The 3 billion personal computers now account for more than 1 percent of all the energy consumed worldwide, while the 30 million servers in use represent another 1.5 percent of energy consumed. The servers cost $14 billion to $18 billion a year in electricity usage. That’s only going to get worse.

To meet its 25X20 goal, AMD said it has to step up the pace of energy-efficiency gains through the use of new technologies and methods. Carrizo offers improvements such as the ability to optimize voltage by adapting it to the task at hand and scaling the frequency as needed.