Snaplex stability / performance issues

I have a single feedmaster + single groundplex setup:

Currently there are 70 active (ultra) pipelines and the groundplex is consuming ~1400 threads. There are additional ultra pipelines that the system is trying to initialize. However, we are encountering severe stability issues:

• we are seeing numerous pipelines failing to prepare in the dashboard
  
• new ultra pipelines take 15+minutes to initialize.

Are there any configuration changes that can be made to improve system stability and increase responsiveness…

Thanks.