In more normal use, with power-saving on, I suspect you could get 4 to 5 hours on the XPS 12, but that's still nothing to write home about.
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Still, these are respectable numbers in my harsh tests, and suggest to me that in more normal use with power-saving on, you could get six hours or so easily on these machines.
The AMD Radeon HD 8000M Series features AMD Enduro Technology, a cutting-edge power-saving solution that scales GPU usage and power based on graphics demand.
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In my test, where I use full brightness, disable power-saving software, leave on the Wi-Fi, and play a loop of music, the battery on the XPS 13 lasted just under four hours, the worst I've seen on an ultrabook.
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In my tough battery tests, where I set the screen to 75% brightness, turn off power-saving features, leave the Wi-Fi on and play locally stored videos until the machine dies, the Surface Pro did pathetically.
The researchers have found that this kind of energy-taxing "idle listening" is occurring during a large portion of the time phones spend in power-saving mode---as much as 80 percent on busy networks.
ENGADGET: New 'subconscious mode' could improve smartphone battery life, supress your WiFi id
The difference between a good NBA team and a mediocre one is its ability to power through these lackluster opponents, saving the struggle for the hard stuff later on.
Even when smartphones are in power-saving modes and not actively sending or receiving messages, they are still on alert for incoming information and they're searching for a clear communication channel.
ENGADGET: New 'subconscious mode' could improve smartphone battery life, supress your WiFi id
They discovered that, depending on the amount of traffic in the network, devices in power-saving modes spend 60 to 80 percent of their time in idle listening.
ENGADGET: New 'subconscious mode' could improve smartphone battery life, supress your WiFi id
My test taxes the computer more than a normal user and involves keeping Wi-Fi on, cranking the screen to full brightness, turning off all power-saving features, keeping email retrieval going in the background and playing an endless loop of music.
In my battery tests, where I turn off all power-saving features, crank the screen brightness up all the way, leave the Wi-Fi on, and play a continuous loop of music, they fell well short of that.
But critics are angry that the energy saving measures will appear as a consultation document, whilst the Bill itself concentrates on creating more power.
BBC: Energy Bill and plans to pay firms to cut energy use due
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