Testing the battery life of a computer requires a specific environment; as you need to ensure that the testing conditions are sufficiently alike that one situation can be compared to another. We wanted to measure the consumption under windows XP and under Vista. For this, we formatted the machine each time, installed office and the latest drivers and the updates for each operating system. The only thing plugged in was the wireless Logitech revolution USB mouse. In order to avoid any variable corrupting the results, we chose to deactivate the Wi-Fi mode and to not connect to the internet.

During the different tests we limited ourselves to the use of Office, the objective being to reflect the use of an average office worker. This is also why we took apart the RAID 0 and removed the second hard drive in the machine. Laptops with this type of configuration are still relatively rare, so it didn’t seem necessary. The brightness of the screen was put down to two notches under the maximum brightness; in each test it is possible to simulate a modest environment and to keep a strict control of the impact of the LCD screen.

Handicapped Vista

Before continuing, it must be pointed out that Vista starts with a handicap. The relative youth of the OS implies that the drivers are more optimised for XP than for Vista. History confirms this, if you remember, Windows 98 lasted longer on battery than XP when it first came out for the same reasons. This means that the figures we received are far from fixed and should change after time with updates and with the launch of new components whose drivers will have Vistae in mind.

Question: between Windows XP and Vista, which OS is best for a user looking for the best battery life possible? The series of tests we have carried out tell us the weight of each OS on each battery and single out the individual impact of certain applications of the operating system.

Aero vs. Luna

The first question is the impact of Aero (Vista’s new graphic interface) on the power consumption compared to Luna (Windows XP’s graphic interface). The introduction of transparency, the 3D desktop and all its remodelling has left some users fearing the worst.

This question stormed the internet even before Vista’s official release and there are still two sides to the argument. Some say that new optimisations of the system’s power consumption should compensate for Aero’s additional power demands. Others claim the reverse.

Both sides through out numbers, but it seemed amusing to us to underline Gateway’s position. For a long time, the manufacturer assured us that, after intensive tests, the sophisticated mechanisms of power consumption reduction went as far as favouring Vista over XP, despite the enhanced desktop.

No results were published though and (as much as we do’ot want to question Gateway’s word) we still ask questions. As we’ve already said, it’s normal for a new operating system to have a reduced power efficiency compared to its predecessor. So Gateway’s words are surprising, to say the least.

It’s also interesting to see that Redmond has taken measures to ensure efficiency. On its Windows Vista blog, Microsoft claims that Aero’s consumes a minimal amount of power. The company says that the consumption of the GPU represents 15-5% of the over-all energy and that Aero only increases this by 1-4%. Finally, Microsoft assures us that the engineers rendered the deactivation of Aero simple and fast for those who would rather do without.