Battery life is as important for mobile computer systems as performance. That is why we decided to pay special attention to this parameter under most typical types of workload. We tested the battery life with the help of Mobilemark2005 testing suite. Note that all the battery life tests were performed with maximum screen brightness and with the disabled automatic shift to StandBy mode.
The first scenario emulated the regular user work in typical office applications. Just as during our performance tests, the hypothetical user ran the following applications on the notebook: Microsoft Word 2002, Microsoft Excel 2002, Microsoft PowerPoint 2002, Microsoft Outlook 2002, Netscape Communicator 6.01, WinZip Computing WinZip 8.0, McAfee VirusScan 5.13, Adobe Photoshop 6.0.1 and Macromedia Flash 5. The script used in this case emulated the routine work of a car dealership employee.
If we compare the results of our performance tests with the results of our battery life tests, we will get quite a bit of new food for thought. Looks like higher performance of the new Core 2 Duo processor has another side to it. The notebook equipped with this processor has slightly shorter battery life that its counterpart equipped with a slower Core Duo CPU. So, the 10% performance increase we have just revealed during our test session costs Merom about 8% of its battery life. Therefore, we shouldn’t retire Core Duo CPUs just yet: they will be a great choice when longer battery life matters more than higher performance.
The second scenario that we used during our battery life test session emulated the usage model when the notebook is used for video playback. In particular, this test shows how long the notebook battery will last during DVD-movie playback via the InterVideo WinDVD 6.0 player.
The qualitative results are the same as in business applications. The system with Core Duo processor will ensure slightly longer DVD playback time when running on battery.
The third experiment we conducted measured the battery life during text reading. The text was displayed in NetScape Navigator 6.01.
Although when you read texts from the notebook screen, you do not spent so much battery resources, the picture hardly gets any different. The mobile systems with Core Duo processor works 6 minutes longer in this mode.
The last fourth scenario was aimed at measuring the battery life when the user is browsing internet. The usage model in this case is very simple: the internet surfing is performed in Microsoft Internet Explorer. The notebooks are connected to the internet via the built-in wireless network controllers that were absolutely identical in our case.
This time the notebooks equipped with Core Duo and Core 2 Duo processors works almost equally long. Although I still have to point out that the system with Core 2 Duo inside shut down 4 minutes earlier.
Summing up all the obtained results, I would like to say that it is not for nothing that the claimed typical heat dissipation of the Core 2 Duo processors is higher than that of the Core Duo. In reality it means that by hitting higher performance they spend more resources when running on battery. However, the maximum difference in battery life we managed to detect equaled only 8%, which can hardly be regarded as a dramatic difference.