Reformatting my 1998-era Sony PCG-Z505-HS laptop. Flashed to latest bios, ACPI works fully in XP. I have a trip-capacity battery, it can last around ~4 hours when power-management is working. All I want is to able to tell the computer "run slow but last long" or "burn like hell". Screen dimming would be nice. Do I want to use ACPI or APM?