Let me ask a basic question here, your Xeons are Nehalem (X55xx/L55xx/E55xx) yet?Yeah that's right you set it using the DAW.
I am having some weird stuff happen though.... I can set to 96kHz with a buffer rate of 512, and with Ableton open, there is no latency at all -- clear as day.
Then as soon as I quit Ableton, the latency comes back..... I've tried playing around adding some negativity to bring the latency down to absolute 0, and even to negative values such as -45ms, but I still get issues as soon as I quit Ableton. Really odd!
Edit:
There has got to be a way to fix these latency issues.... This is NOT acceptable
In my DAW I can set the sample rate to 192kHz @ 1024 bit size and I have a 12.8ms overall latency, which is within the 13ms allowed range, but as soon as I exit the DAW, the latency issues persist.
I've tried switchin USB ports with no luck -- wonder if it's my USB cable? hmmm I didn't have any issues like this with High Sierra though -- and I think now this was one of the reasons I decided to stay on that OS for as long as I did.
Nehalem dual processors are not supported after 10.14.3 - in reality support officially ended with 10.11.6, but the problems started with 10.14.4. This is not an OpenCore issue.
The first collateral damage of the Nehalem support being removed by Apple with Mojave and later releases are audio stuttering/cracking. This is not news and if you want to have audio working correctly after 10.14.3, you need to upgrade to Westmere Xeons.