Our architecture places SSIS packages on their own servers, away from our SQL Servers. This reduces contention on the sql server boxes themselves and makes the SSIS servers independent, allowing resources to be adjusted accordingly. There are a few processes where we use SSIS 'Raw Files' to improve performance. Originally we put the raw files on a remote file server and performance was acceptable. The idea was floated that putting the raw files locally on the SSIS server should improve performance by reducing network traffic.