8. CPU

I selected the 3.0GHz P4 with HyperThreading.  Basically a hyperthreaded CPU appears as two CPU's to a SMP capable operating system.  There are discussions as to how much this actually increases / decreases performance.

Dell Picking Slip Inspiron(TM) 9100 Intel(R) Pentium(R) 4 Processor w/HT 3.0 GH
Linux identified as (/proc/cpuinfo)
vendor_id: GenuineIntel
model name: Intel(R) Pentium(R) 4 CPU 3.00GHz
cpu MHz: 2992.756
cache size: 512 KB
flags:
 fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe cid xtpr
bogomips:
 5931.00
driver X86_PC, MPENTIUM4, SMP, I8K, MICROCODE, and others!
use frequent

8.1. Hyperthreading

To enable Hyperthreading, you need to compile the kernel with SMP (symmetric multi-processor) support, or use a precompiled SMP kernel.
CONFIG_SMP=y
CONFIG_NR_CPUS=2
CONFIG_SCHED_SMT=y

8.2. ACPI

Most ACPI associated functions are controlled by the BIOS, so there's no point in use a user-space tool to do so.  This includes fan speeds and display brightness when you plug in / unplug the power cable.

The functions that I have customised for linux are closing the lid, and speedstepping when the power is unplugged.

8.2.1. Lid

This is important, as I had some burn in on the LCD.  I used to close the lid at night when the laptop was compiling, and just let the screensaver take over, but on occasion I had the screensaver off, and so my desktop background left some anomolies behind!  Luckily this has now disappeared.

8.2.2. Speedstep

Speedstep is Intel's method of reducing CPU power consumption when running on battery power.  The idea is to lower the speed in defined steps (hence "speedstep") depending on the power source and the laptop performance.  You can run any speed at any time, but generally it makes sense to use maximum speed when the power is plugged in (otherwise the laptop will be sluggish), and variable performance when running on battery.

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