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

Overall & DVD Playback Performance

Now that we've looked at all of the tests individually, let's see what they total up to be. We already established that the Auto PowerNow! mode increased battery life by around 21% which can vary depending on the type of applications you're running, but for the most part it should fall somewhere around that figure. Now it's time to see at what overall cost this added battery power comes:

Not bad at all, the overall performance hit is nothing major at all, in fact it is definitely worth the results. The Max Battery Life setting is probably something for, as we mentioned before, those that are running Office applications only or those that are in desperate need of extended battery life in order to finish a simple task.

Using the Video2000 benchmark we took another CPU benchmark to see if the performance hit that resulted from using the Auto PowerNow! mode changed much under different conditions, and as you can see from the above results, it didn't.

To illustrate exactly how much free CPU time there is when you're doing even a "CPU intensive" task such as playing a DVD, let's take a look at the below chart. The benchmarks are split into three groups, 3Mbits/s, 6Mbits/s and 9Mbits/s, which are all DVD streams, the higher values are obviously more complex streams and require more CPU power to decode. So let's take a look at the results:

Running at full speed, while playing a 6Mbit stream, the K6-2+ still has around 42% of its CPU time free, enabling PowerNow! in Auto mode takes away some of that free CPU time by underclocking the processor. The effect is really noticed at the points of lower CPU utilization since there is much more room for PowerNow! to step in and drop the clock speed of the processor.

According to AMD, as well as what we've seen in our tests, generally when playing back a DVD, the K6-2+ will hover around 350MHz for most scenes if PowerNow! is left in Auto mode.