CPU spiking with iZotope Neutron 4 and Ozone

maybe what you need to do, is to try exactly the opposite (which is using smaller buffers), at least according to iZotope, on this article:

https://support.izotope.com/hc/en-us/articles/6658119858065-Reducing-Ozone-s-latency-and-CPU-usage

also try to do the suggestions described in this article:

https://www.izotope.com/en/learn/10-tips-for-winning-the-battle-against-cpu-overload.html

other than that, i can not tell you much... i have a, more or less, similar system which is working perfectly at 128 samples buffer size.

apart from that, the only thing you can do is follow some generic (but really fundamental) instructions for lowering your CPU usage, such as:

1. Identify the process that's causing high CPU usage (use task manager to check this!), it might not be an audio process after all
2. Eliminate unnecessary background applications and services
3. Check for other outdated drivers and software (especially drivers!)
4. Reset power settings and always use "High Performance" plan
5. Disable P2P sharing, Cloud services sync and, in general, avoid to use network apps while making music
6. Disable Cortana and other Microsoft apps who are running constantly in the background.

NOTE: Also consider that most iZotope plugins are meant for post-production (mastering etc) so, using them on simple every-day jobs is not really wise, especially since your system obviously can't handle them. If for example you only need to lower frequencies around 15Khz by 3dB, in your hi-hat channel, the basic Ableton EQ can do the job just fine! ;-)

Woooooow this is really heavy!!! Only a top-class Pro studio can handle all those at the same time!

My advice, never do mastering on the same time as you producing! Mastering is done later, on the exported .wav, either through Ableton or other DAW (but this should be a separate process, where the only thing in your DAW will be the exported .wav and nothing else), either on a dedicated audio editor (SoundForge, Wavelab etc.).

In fact, it is much better if you not put anything at all on the master output channel, or perhaps a limiter if necessary. For a good mastering, the exported .wav must be as "clean" as possible and since we are talking about mastering, it is an extremely demanding work which requires a deep knowledge about audio and it is best to leave to the professionals.

I already had an almost 20 years of experience before i dared to make my first own mastering. And of course it is obvious that, using few random presets that might make your song to sound "nice" or "loud" is not considering as mastering, not by a long shot.

By using Ableton internal plugins or other, much less demanding 3rd party plugins, and maybe 1-2 instances of Neutron or Ozone... :-)

...and also keep in mind that dynamic plugins are far more CPU demanding than standard plugins, so, for example, use a standard EQ and not a Dynamic EQ.

Helpful note: Consider limitations not as an obstacle but as a chance to explore and experiment with what we have and what we can handle... you will gain a lot of precious knowledge! Easiness is good, but it rarely gives real knowledge. 🙏