Choosing high-grade and efficient server components for your system makes a big difference in terms of reliability and performance of a system.
The following monitoring graphs show the CPU bottleneck of handling ~300 'All Out' CPS traffic (without media proxying at all) on server having 2 X Intel Xeon CPU E5-2620 2.00GHz (12 physical cores in total) configuration.
System with 16+ physical cores CPU configuration works steadily under ~300 ' All Out' CPS with sane CPT stat of less than 100ms.
Here's an example graph showing traffic on a Sippy Media Gateway. On the left side, it shows the Packet Per Seconds, CPU usage and Bandwidth usage when running a Broadcom Network card. The day after we installed a server grade Intel Network card. As one can see, at the equivalent PPS and bandwidth levels, this system had a 15% CPU reduction, and overall, the system was able to handle significantly more network traffic.