As there is some overhead to process activity, it might take long time to process huge data using many activities.
So, one of the solutions is to reduce total number of processing activities.
For example, using LINQ and/or InvokeCode activity might help you.
If you can share specific requirement, we might be able to provide the solution.
Do you know which activity is consuming more time? In the modern designer we have a feature Profile execution. It helps to check the performance of the entire workflow and it helps you to fine tune the project.
UiPath 2022.10 updates| Profile Execution |How to Identify performance issues in Workflow execution?
Always using for each row loop will take lot of time to process if we have lot of rows.For above requirement you mentioned like getting the value from 3 columns and write those values in another output excel we could use vlookup by using excel formula to speed up the performance it will be very quick if we use vlookup functionality.
For to implement the above logic we could use write cell activity to write the vlookup formula in the second row after header value and use fill range activity to fill all the desired rows by dragging the vlookup formula. Let me know if you need any further assistance with logic.
Or if you don’t have Comman values in the both excels we could go for copy and paste range by using invoke code activity by writing vb code. This is very simple approach to automate above requirement. Let me know if you need sample vb code. Thanks