Is there limit for how many Validators (full = 32ETH) can be running on/with single Consensus client ?
Based on schema (below), only Consensus client is connected to p2p network and validators are only communicating with it internally. Trying to figure out if high number of validators affects CPU/Network usage of Consensus client itself, and so if it's much more efficient to run many validators on single server, or there is any benefit of being "1-validator per node" staker.
(Schema from eth-docker.net)
Best Answer
There is no hard limit to the number of validators you can run on a single machine. With any modern hardware, you can easily run hundreds if not thousands of validators. The additional resources usage for adding 1 more validator to an existing setup is negligible. Running multiple validators will require slightly more network usage as they will need to listen to more subnets.
You are more likely to want to limit that number for risk management than for any limit in terms of hardware resources. The usual suggestion is to limit any single machine from running more than 1,000 validators since any issue with that machine will likely cost a lot in terms of downtime penalties. At that point, other enterprise solutions should be considered.
Adrian Sutton has a nice post that explains the cost of adding more validators.