Nvidia Corp. GeForce GTX 1070 graphic processing units (GPU) sit stacked inside a 'mining rig' computer, used to mine the Ethereum cryptocurrency, in Budapest, Hungary, on Wednesday, Jan. 31, 2018. Cryptocurrencies are not living up to their comparisons with gold as a store of value, tumbling Monday as an equities sell-off in Asia extended the biggest rout in global stocks in two years. Photographer: Akos Stiller/Bloomberg , Bloomberg