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MMCSS and Windows 8 and 10
Old 14th August 2017
Gear Nut
danharr's Avatar
🎧 10 years
MMCSS and Windows 8 and 10

I recently read in a Steinberg support bulletin that Windows 10 MMCSS allows only 28 threads, or 14 logical cores. This means that Cubase and Nuendo may suffer dropouts on systems with more than 14 logical cores. Steinberg actually suggests that downgrading to Windows 8.1 is a possible solution, or disabling cores is another fix. Surely, with all the new CPUs from Intel and AMD coming down the pike- there must be a fix in place or on the way from Microsoft? Seems odd that we would have to avoid new powerful computers or run Windows 8.1 for best performance running Nuendo.
Old 14th August 2017
Lives for gear
It's all a ploy between MS and Intel.

AMD beat Intel to market and MS threw a curve to squash any momentum advantage it would have given. Intel releasing specs and just their top chip to show they were in the game and not sleeping bears it out. When Intel's ready, MS will open the tap, benchmarks will be done side by side and any first mover advantage will be muted.
Old 15th August 2017
Gear Nut
danharr's Avatar
🎧 10 years
Thanks, Nate-
I wonder if that's really true!?!?
It seems odd that Windows 8 can access more cores real time than W-10.
Old 15th August 2017
Lives for gear
thedberg's Avatar
This has been discussed to some depth in other threads here at GS. People who build DAWs for a living testify to suppling dual Xeon computers with these amounts of cores to customers without problems. The issues are clearly dependent on more factors than just cores.

And obviously MS is not generally limiting the amount of cores on purpose. They want to sell and run servers...
Old 22nd February 2018
Lives for gear
Psychlist1972's Avatar
🎧 5 years
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.
Old 26th April 2018
Lives for gear
2 Reviews written
🎧 10 years
Hi.. afaik, the workaround involves limiting Cubase to use less cores, no?
Or is there a workaround that can be applied to allow Cubase to use say 20 threads of a 10 core machine?

Also, any news on the plugin limit Pete?

Finally, do you know if the MMCSS issue affects pro tools? I have not been able to find any definitive info on whether Pro Tools behaves like cubase and schedules 2 mmcss threads per core?

I am *still* stuck on whether to move to windows from mac, so i can buy a computer for half that price that will be uber powerful.. But for my growing needs, I need to be able to make use of, at minimum, an 8 core 16 thread machine or 10 core, or even 14 core would be preferable. Something with a minimum clock speed of 3GHZ with the latest intel architecture.. An imac pro 10 core is what i was looking at but i cant' afford it.. I could build a beasty 7940X or 7900X, with good cooling, zero throttling unlike imac.. something made for sheer performance, not power saving. And it would cost 6 grand vs 11 grand in AU.

BUT.. these 2 issues , which are huge to me, is what halted me a few months back.. SO.. hopefully.. progress?

Cheers and TIA!
Old 29th April 2018
Lives for gear
🎧 10 years
Well FWIW, I've read about this issue in the past but I'm running an AMD 1920x that has 12 cores/24 threads and I don't get any dropouts with Cubase on Win10. It's POSSIBLE (although it varies greatly from project to project) for Cubase to load up all 24 cores of this CPU to near enough 100% in Windows Resource Monitor with no dropouts or issues at all.
Old 29th April 2018 | Show parent
Lives for gear
🎧 10 years
Originally Posted by TNM ➡️
I am *still* stuck on whether to move to windows from mac, so i can buy a computer for half that price that will be uber powerful..
I made that same transition several years back and very happy to have done so. Whilst I do slightly prefer Mac OS for general use, if you want Cubase horsepower for a reasonable price, Windows is the way to go IMO. Also (and this is highly anecdotal!) I get the feeling Cubase is a little more bug prone on Mac OS in recent years.
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