Imagine you have $50000 to build ETH mining farm, what HW you recommend?

[Undefined31415]

Will a couple hundred thousands of old android phones be viable to setup as a mining farm? They are already being setup as clickers and bots.

It's probably not worth the effort for the hashrate you'd get. Phones have basically no cooling system, so it would be very difficult to constantly run them pegged 24/7 without running into problems.

[marlyn]

omg no buy vega 56, $399 right now they hash at 40 eth vs 31 and cost the same and make even more mining cryptonight

Thanks for your answer. Are you sure about hashrate? I bought XFX Radeon RX Vega 64 8G HBM2 XT Air Cooled Black Edition 2 weeks ago, for testing purposes and today I returned it back to shop for 2 reasons:
- on Windows 7 64bit was hashing only 36MH/s average (max. 39 for short while).
- on simplemining OS it wasn't working at all

[Shnikes101]

omg no buy vega 56, $399 right now they hash at 40 eth vs 31 and cost the same and make even more mining cryptonight

Thanks for your answer. Are you sure about hashrate? I bought XFX Radeon RX Vega 64 8G HBM2 XT Air Cooled Black Edition 2 weeks ago, for testing purposes and today I returned it back to shop for 2 reasons:
- on Windows 7 64bit was hashing only 36MH/s average (max. 39 for short while).
- on simplemining OS it wasn't working at all

Yes. If you read https://bitcointalk.org/index.php?topic=2002025.0 you can figure it out. I believe best I've seen is 44 mh/s at 150 watts