[guitardom]

The "spiking" will vary with the plugin selected and buffer size selected. Some plugins want more "time" with the cpu than other plugins. Those types of plugins will not work as well at lower buffer settings. Again, its always been this way. Any plugins known as "cpu heavy" are heavy BECAUSE they need more "time" with the CPU. When the HW Buffer is set low, the system (Pro Tools) is calling the cpu FAR more often in an attempt to reserve and take cycles that it can dedicate to latency. This is getting in the way of or "interrupting" other processes that are wanting more attention, like some plugins. Its why problematic drivers or drivers with heavy footprints like wireless drivers for instance will ALWAYS reduce system performance at these times and why bios settings that cause throttling and cpu fluctuations cause problems. Again, plugins and software determine the need, but overall system power and how well your system is optimized is the overall determining factor of the difference between high and low buffer settings with live inputs.