How many instances of the Plugins you need to use in order to reproduce the same result? Are you running them at mono or stereo?
Check our guide for PC optimization, and then analyze your system using Latencymon. Your hardware can be quite powerful, but you also need to consider the real-time performance of your system.
We recommend running your projects at 44.100 Hz / 128 samples. Try to measure the CPU consumption of one instance of the Plugin with those settings using the performance meter inside Reaper. If you wish, you can send your screenshots to support@neuraldsp.com.