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.
When all the numbers are added, the Panel Self Refresh technology can result in the laptop saving up to 85% power while it is being used. Please understand that this doesnât mean that battery life will last 85% longer. This saving only occurs when the computer is idle and the display isnât refreshed.