EventStore does not use all available resources

I’ve pushed 4M events to ES. There are 20 projections and 10 subscriptions.
Master node consumes about 40% CPU and it takes about 4 hours for all projections to handle all events.

Memory and IO are also not 100% utilized.

Is there any configuration setting limiting maximum CPU usage or any other reason that prevents ES from using all available resources to process events as fast as possible?