Last updated: 20210611
Short answer: Mobile 2G network
Long answer:
Latency/Ping/Reaction time is more important than bandwidth (maximum download and upload speed).
What matters is how STABLE and FAST your internet reacts and responds, not how fast your DOWNLOAD and UPLOAD speed can get.
It’s not the speed that matters, it’s connection quality.
Fluctuating internet speeds and connection can result in less profits as your rig won’t be able to send your mined shares to the pool or Blockchain itself in case of Solo mining on time.
Even 2G internet should work without any hiccups on a 4 GPU mining rig, as long as the quality of the connection is good, and does not disconnect often.
Poor internet connection often results in invalid shares so that should also be noted.
You don’t need a high speed internet for that a decent 2Mbps link will do just fine as you just need to connect to the blockchain network.