Users running Windows Vista on laptops may see batteries draining faster than they expect, Microsoft said in a warning, because some wireless access points aren't configured to take advantage of the new operating system's Wi-Fi power-saving mode.
In a recent post to Microsoft's official Vista blog, senior product manager Jason Leznek spelled out the company's last-minute decision to change the default power setting of wireless adapters to "maximum performance."
"Test results from Microsoft and our customers show that some Windows Vista beta users experienced connectivity problems when connecting to public Wi-Fi hotspots," wrote Leznek in his post. "In many cases, the root cause of the problem is access point or router hardware which is not compatible with the 802.11 power save protocol."
Rather than leave the wireless access card in "power save" mode -- which reduces battery drain by periodically putting the card to sleep -- Microsoft switched the default to a more power-intensive mode, one usually reserved for times when the laptop is connected to AC power, Leznek noted.
"However, this power savings scheme for 802.11 wireless adapters depends on cooperation of the access point," Leznek wrote. "The problem is that many access points do not implement or support the power save feature correctly."
To make sure as many people as possible would be able to connect to wireless hotspots, Microsoft made the settings change before Vista moved into its release to manufacturing (RTM) phase last month. "The obvious downside is a potential decrease in computer battery life," Leznek acknowledged.
OEMs can modify the default setting before shipping Vista-equipped notebooks, Leznek pointed out; users can also change the power-savings mode through "power options" in Vista's control panel.