I do apologize for not being more specific.
The network is what we referrer to as the file created and saved using hark_designer.
We have conducted a few test and have not seen a major increase on the load on our CPU when using HARK 3.0 installed on Ubuntu 16.04. For the tests, the network used localization and separation nodes, to be more specific LocalizeMUSIC and GHDSS.
We have however, found that the CPU load was increased significantly(up to 60% in our tests) when installing HARK 3.0 on Ubuntu 18.04.
The source code is the same for both Ubuntu 16.04 and Ubuntu 18.04 so, the reason for the load increase may lie somewhere else.
As you mentioned, you are currently using Ubuntu 16.04 so the sharp increase in CPU load should not have effected your environment.
To get to the bottom of the increase in CPU load you have noted, we would like to see the parameters and nodes used in your network file to see if we can replicate your results.