Inside your computer are several smaller ones, which must work together for best performance. Getting them to do this, rather than pulling against each other, can make quite a difference to how your machine behaves, but most come out of their boxes inadequately set up because there isn't enough time or incentive for the manufacturers to do it for you - they mostly choose standard CMOS settings to suit the widest circumstances (and keep BIOS problems to a minimum), which are often the slowest. The BIOS Companion is a book that: Explains those secret settings in the CMOS Setup Contains a wealth of data for troubleshooting Includes Error and POST Codes Is a constant source of reference Reduces the need to call Tech Support Helps you speed up your machine Helps you increase reliability