AMD's K6-2+ in Notebooks - Evaluating Performance with PowerNow

PowerNow! Operating Modes

On the motherboard and software side of things, PowerNow! is fairly easy to implement. First of all, the motherboard must have BIOS support for the processor and the technology (obviously). On the Operating System side of things all that is required is the installation of a PowerNow! driver that should be pre-loaded on all laptops before making their way into the hands of the consumers. Unfortunately AMD does not make the driver available for download on their site, so you'll have to get it from your notebook manufacturer if you have to reformat your system.

Obviously there are some situations where you need every last bit of performance you can get and others in which you could care less about performance and are primarily concerned with battery life. Because of the variety of operating conditions you can run into, PowerNow! has a set of modes that govern the way it works.

The operating modes are fairly simple and very self explanatory:

High-Performance Mode: This mode keeps the CPU running at full speed and delivers the highest performance possible, at the same time it also requires the most amount of battery power and can shorten battery life significantly.

From AMD's PowerNow! Demo

Battery Saver Mode: In this mode, the processor runs at the lowest possible multiplier state supported by the EBF Divisor (currently 2.0x resulting in a 200MHz clock speed). This results in the lowest possible performance while providing the longest battery life.

Automatic Mode: This is the mode that we were referring to earlier when illustrating what PowerNow! can do. In Automatic Mode, PowerNow! can adjust the clock frequency and voltage of the processor according to the demands of the applications being run while optimizing for battery life. Through the use of the aforementioned PowerNow! driver which monitors CPU usage, the CPU when running in Automatic Mode can balance out performance and battery life.

The real question is, what kind of performance sacrifice do you make for the extended battery life? We'll get to that in a bit, but for now let's look at the test platform we used to evaluate the performance of AMD's PowerNow! technology.