Whether you get a new phone every few years or every month, the question becomes what to do with your old one. Do you sell it on a site like eBay or Swappa? Do you stick it in a drawer for a rainy day? Older phones, especially older flagships, still have a ton of power left in them. To demonstrate what they can do, Samsung is launching an upcycling program that shows how people can re-use older devices.
Samsung’s C-Lab, an engineering team that focuses on creative projects, is heading up the venture. Their headlining project at Samsung’s recent developer conference was a 40-stack of Samsung Galaxy S5s turned into a Bitcoin mining rig. Not only were the phones able to mine Bitcoins, they were able to do it more efficiently than a desktop computer. In fact, eight Galaxy S5s can mine more efficiently than a computer with an Intel Core i7 2600.
source - https://www.androidauthority.com/samsung-bitcoin-mining-rig-810977/amp/