As part of QPR Suite 2017.1.0 testing, we implemented a performance test where 100 users browsed portal simultaneously. This resulted a feature which improved the performance by 83% during high loads. Additionally, it was discovered that setting up multiple Web Application Server instances - even on the same machine - would further improve the performance significantly. In the tested scenario setting up three additional instances improved the performance by 75%.
The report is available here.
If you have any questions, I would be happy to answer them in this thread.