Workflows - Load testing / limits

Does anyone know if there are load limits to generating workflows.  We are triggering scheduled workflows every 30 minutes, for all ~80 servers. (Yes I know that is fairly small numbers compared to most of you). Has anyone had issues with workflows hitting a performance/load limit. We may want to increase the frequency of the workflow, and definitely increase the server count.

Each workflow is fairly simple, updates custom fields, tags, and runs simple powershell scripts.

Cheers

Simon