I'm not following, by hardware do you mean standard nodes or mining?
Hardware requirements required to host and replicate the entire Ethereum blockchain.
eg: It's possible to host a full Bitcoin node on a RasPi and USB drive. The Ethereum node software would laugh at a RasPi.
Extreme example, I know, but I've read Tweets from seasoned network techs who gave up trying to fully sync an Ethereum node on high-end servers.
$45 dollar Intel nucs and similar form factor full x86 mini pc's with linux would run it with ease. I got quite a few Zotac dual core machines with 4gb ram, 256gb hard disk for that $45. There are plenty of similar priced machines, they all use low wattage.
Might need a larger 2.5 drive but it shouldn't be too extreme to run a node.