laptop battery

This information is elsewhere on the net, but not necessarily easy to find, so I’m “re-documenting” it here Sony laptop battery while I still remember it from my work in this area back in 2002-2005. These states are mapped for Windows XP terminology only, but a great deal of IT machines are still out there that use XP so it’s probably still relevant for another year or so. The impetus to write this down was due to my wife’s work laptop “being loud all the time”. I took a look and discovered that it was her fan that she was complaining about. Since it had the Centrino Mobile Technology sticker, I knew the laptop batteryprocessor had to be Pentium M or later, fully supporting Intel Enhanced SpeedStep Technology, so I changed the power Sony PCG-R505 battery profile to allow the CPU to enter a low power state while the laptop was plugged in (which is almost all the time). About ten minutes later, everything was perfectly quiet (the fan having stopped running for the first time).

Brief Background
Because battery life was becoming a bigger and bigger concern on laptop and notebook computers, Intel introduced Intel SpeedStep Technology to their mobile processors that allowed the clock frequency (how fast the processor ran) to be reduced. The original processors would switch to a low frequency (or performance) mode when the laptop was unplugged and running on batteries. The slower frequency used less electrical power and, therefore, battery life could be increased. Later Enhanced SpeedStep Technology was introduced that could laptop batteryswitch between a low frequency and high frequency state as needed Sony VGP-BPS10 battery by the application - if it was a low demand application (like reading a Word document) then the processor could remain in low performance mode, but jump up to high performance when you briefly ran your Excel calculations. In this mode, the processors mostly stayed in low performance mode (due to how people use computers - bursts of activity that take a small amount of time separated by long periods where the user is just reading or thinking) and jumped up for a few seconds at a time to a high performance mode Sony VGP-BPS9 battery . This way, you almost got the same battery life as being in low performance the whole time, but had almost the same responsiveness and performance of a system running all the time in high performance mode. Later, with the release of Pentium M (the first processor sold as part of Intel Centrino Mobile Technology launched in March 2003), support for multiple frequencies (not just a high and low performance, but points in between) was added to further fine tune this feature.

The problem is, even if you understand your computer did all of this, how do you make sure the technology is on? With Windows XP, the settings are hidden and implied by specific power schemes.

Windows XP Power Schemes
In Windows XP, you can access the Sony VGP-BPS8 battery power profiles by going to Control Panel -> Power Options -> Power Schemes. There are a number of Windows XP built-in power schemes (I guess they’re called power schemes - not profiles… I’ll use power schemes from now) that I’ll list below in table form. Each power scheme has a group of settings for when you are Plugged In and Running on Batteries with respect to monitor turn off, hard disk turn off, standby, and hibernation. From this user interface, it’s easy to assume that’s the only difference between each of the power schemes, but in truth there are hidden meanings to each setting when it comes to how the processor is programmed to react to different loads (computing tasks). Here’s how it boils downSony VGP-BPS5 battery :

Built-In Scheme Plugged in behavior On battery behavior
Home/Office Desk CPU(s) run in highest performance state CPU(s) intelligently select a performance state based on demand
Portable/Laptop CPU(s) intelligently select alaptop battery performance state based on demand CPU(s) intelligently select a performance state based on demand
Presentation CPU(s) intelligently select a performance state based on demand CPU(s) begin in lowest performance state and then get slower and slower via software manipulation
Always On CPU(s) run in highest performance state CPU(s) run in highest performance state
Minimal Power Management CPU(s) intelligently select a performance state based on demand CPU(s) intelligently select a performance state based on demand
Max Battery CPU(s) intelligently select a performance state based on demand CPU(s) begin in lowest performance state and Sony VGP-BPS3 battery then get slower and slower via software manipulation