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Old 22nd February 2018
Necrothreading here because this just came up in a search. It's not about conspiracies, or about limiting cores. The "14 cores" bit is very specific to one piece of software.

Steinberg and other DAW creators who have reached out on this issue have a workaround that can be selectively applied to get around this. It's not published in the wild becuase there are system-wide performance implications to just opening it up to some arbitrary large number, and I don't want the workaround to show up in some tweak app, blindly applied.

Steinberg is also working on a long-term solution with their products.

Link to feedback hub with description:
Feedback Hub - Windows Insider

In Windows 10, the Multimedia Class Scheduler Service was moved from user-mode to kernel-mode, to reduce overhead and improve integration with the kernel thread scheduler.

As a side effect, a per-process limitation of 32 registered threads was introduced. Applications which register a large number of threads in a single process may see MMCSS registration fail in Windows 10, in circumstances where it succeeded in Windows Vista through Windows 8.1.

We are looking at how to address this.

In general, Microsoft recommends the following for developers:

* Prefer using the Windows Real-Time Work Queue API Real-Time Work Queue API (Windows) over manually maintaining a set of dedicated threads.
* Be prepared for MMCSS registration to fail, since MMCSS resources will vary from system to system, and from even from time to time, depending on what other applications on the system are doing.