There were four basic materials that the Egyptians used to build the pyramids: limestone, pink granite, basalt, and alabaster. Each type of material had a diverse use. Limestone had, for the most part, two uses.
To answer your question: The useful lifespan of a CPU is about 3-4 years. My guess on the technical lifespan under full load is closer to 8-10 years if nothing else breaks and takes the CPU with it. The reasons: High Performance Computing Clusters usually keep the computers for 3-4 years.
Life of a PC laptop. I have a Toshiba Satellite that I bought in 2004, and I've been thinking about upgrading to a new macbook. What is the average lifespan of a PC laptop? I use mine everyday for school and work, and it just seems like it is wearing out. I've heard anywhere between a year and five years, so just wanted to get a general opinion before really searching for something else.