A CPU 14 that is a brain of the entire computer system 10 executes various types of programs under the control of an OS. The CPU 14 can be one of Intel CPU chips, that is, a Pentium, an MMX technology Pentium, and a Pentium Pro, a CPU made by AMD or other companies, or an IBM Power PC. The CPU 14 is configured to include an L2 (Level 2) cache that is a high-speed memory for reducing total access t