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Laptop CPU Control
In order to conserve on battery usage, many laptops have CPU control that can be controlled in the BIOS. This control idles down the CPU (dynamic frequency scaling) when the laptop is unplugged from AC power and running on battery only. Modern operating systems also contain drivers and software “built-in" to allow the CPU to be throttled based on power settings in the operating system. This throttling not only conserves on battery power but also helps to lower CPU temperature.
CPU throttling affects application and operating systems performance. Power users may want to disable CPU throttling to gain the performance they need, whereas average users may want to enable CPU throttling to save on battery usage. Controlling CPU speed and power is based on an individual user’s needs and the applications she wants to run.
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Power Management and CPU Control
Microsoft's Windows XP has CPU management built in the power settings in the power management console. One way end users can regulate the CPU's speed is by changing the power schemes. Settings such as Home/Office Desk keep the processor speed at the normal rating. The Portable/Laptop power scheme ensures that the CPU will be idled down. When the power management is changed to Max Battery, this process will slow the CPU to lower levels as the laptop's battery becomes weaker.
Microsoft's Windows Vista has one of the most advanced power saving management features available. Much like in Windows XP, Windows Vista allows the user to adjust the power management features allowing the CPU (and other resources) to be throttled back or use less power.
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Processors and Power
CPUs today are manufactured with power conservation in mind. Both Intel and AMD contain information built in the processor to allow the processor to be used efficiently with mobile computing saving on battery life while giving the best performance. The line of mobile processors offered by these two chip manufacturing giants are designed for throttling offered by modern BIOS and operating systems.
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Third Party Software
SpeedswitchXP 1.52 is an excellent application that allows for the maximum control of CPU speed and control. This third party software insures that your CPU can step down and save power when needed or insure your computer is putting out its maximum speed. Although this software is more than three years old, it is still very effective and allows your computer's CPU to be controlled as necessary.
Other applications that detect CPU throttling are the RMClock Utility and CPU-Z. CPU-Z does not control throttling but allows the user to see the speed and details of their processor. CPU-Z in the pictures below shows power settings (before and after) that affect the CPU's performance.
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A laptop's CPU speed and performance can be affected by the CPU's power settings or third party software. Users can weigh the options of power vs. battery savings after analyzing what programs are used and what speed (CPU power) is needed by the end user. These settings and third party software is a way to control your CPU based on your usage.