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 The Computer Buzz May 13th, 2010     

Nome and Paul Van Middlesworth - owners - The Computer Factory

More on CPUs

Last week we discussed CPU speeds and benchmarks. We concluded that AMD CPUs provide better performance dollar for dollar on desktop PCs than its rival Intel. The CPU (central processing unit) is that tiny one-inch square “chip” that defines the limits of power in your PC. The CPU sits in a socket on the motherboard and is dwarfed by the heat sink/fan assembly on top.

The copper or aluminum heat sink is in contact with the CPU. The heat flows from the CPU into the heat sink and is then dissipated by the CPU fan blowing air through the heat sink. Warm air then exits the case through the power supply fan or an out-flowing case fan.

CPU’s generate heat as they turn on and off their transistors at their designated “clock speed.” Ten years ago both Intel and AMD CPUs had forty million transistors blinking their tiny eyes a billion times per second. Today’s multi-core CPUs have upwards of one billion transistors operating at three billion cycles per second.

As transistor counts and clock speeds have risen, CPU manufacturers have countered the consequent heat problems by developing ever-smaller transistors and circuitry on the CPU chip. This lowers power requirements and subsequent heat generation. While today’s CPUs are hundreds of times more capable than those of ten years ago, the power requirements (and thus heat generation) have remained fairly constant.

Power consumption and heat generation are far more important when selecting a notebook PC than they are for a desktop. Notebook PCs cannot get rid of heat as efficiently as desktops because of size and space limitations so laptop have “low power” CPUs. This reduces heat and enhances battery life but sacrifices performance.

Most of the newest ten-inch netbooks use the Intel Atom 1.66GHz CPU. The performance of this CPU is equal to that of a ten year old Pentium III 1.3GHz but it can get up to eight hours of operation from its 6 cell rechargeable battery. Most notebook PCs run faster when plugged into external power than they do when running on battery alone.

Some users buy laptops for the convenience of being able to use them in two or more locations, like work and home or perhaps at two different seasonal homes. These users would probably buy a somewhat more powerful “desktop replacement” notebook with perhaps a 17-inch screen. Power, heat and battery life would not be factors because the PC would always be plugged in during use.

If the user must operate the notebook for long periods of time away from an external power source, battery life is key. This user will want a 12 to 15 inch PC with an “air card” for Internet connection. When the major PC use is Internet related, CPU speed becomes a non-issue. This user will need a notebook with the best battery (amp hours) and lowest power consumption. In notebooks there is no clear choice between the processors from Intel and AMD.

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