Increasing Performance on Windows

DISCLAIMER: Due to the nature of discussion following this thread, all content has been omitted except for the instructions provided with the intent of improving the performance of running local applications on the Windows operating system.

There remain no quantitative reports or official benchmark tests to support the author’s arguments, therefore, all of the following information exists as a purely open possibility, and subject to one’s discretion.

From the start menu:

Right click SC

  • More → Open File Location

Now, for sclang, scsynth, scide & supernova, as well as all application shortcuts leading to them:

  • Right click → Properties

  • Compatibility → Run as Administrator

  • Apply → Ok

  • Right Click → Repeat

Windows+X → Task Manager

sclang/scsynth → Right Click

Go to Details → Right Click

Set Priority → Above Normal

* Priority level Normal is reset for each spawned process
* Priority level High should be tested in careful isolation
* Priority level Realtime will immediately crash the OS

It’s a useful strategy to view all running processes under:

Users → Current User

Versus viewing all user & system processes inclusively.

Hi Rainier,

Could you provide some information on what performance advantage is achieved by performing these steps?

It should be noted that running applications as administrator is typically not recommended as it poses additional security risk.

As for priority levels - I thought that SC does some priority levels management even under Windows, but I don’t know for sure. Particularly for scsynth, I believe that the audio thread has a different (higher) priority than the main process (or so I thought).

In any case - it’s best if the advice is backed by at least empirical evidence, otherwise it might backfire.

I once empirically & royally crashed Windows immediately upon setting a single process to “Realtime” priority… Never do this.

I was only joking about using Windows.

All jokes aside, I feel the OS fights with SC less when ‘Run as Administrator’ is selected versus a normal run option.

It’s not clear what ‘Run as Administrator’ actually does at this moment… aside from the obvious permission inheritance applied to the specific process on launch.

It is the second in a long list of options shown when right clicking the shortcut to launch an app, and to bind this option to every launch, it’s under the ‘Compatibility’ settings in Properties, along with other miscellaneous & performance related settings.

I’m sure & while this may be correct for SC under the hood, from the perspective of the task manager UI for all running processes & services, all instances of a launched application (a running process) are represented above the hood as having the following options for
thread priority:

-Below Normal
-Above Normal

All running application processes encounter an initial thread priority value of Normal upon each successive launch.

This remains true for scide.exe, sclang.exe, scsynth.exe, & supernova.exe.

All the best,


- Rain

OS X is by far SC’s favored platform.

citation needed :slight_smile:

First of all, don’t use the default task manager, use something decent like “Process Explorer” by Sysinternals (Process Explorer - Sysinternals | Microsoft Learn). Then you would see that the priority shown by task manager only applies to the main thread. If you double click on the process you can get a view of all the threads and their respective priorities.

As @MarcinP correctly points out, SC already sets the priority of the audio thread to “time critical”. There is absolutely no point in raising the priority of the main thread because it sits idle until the end of the program (at least on Windows and Linux, on macOS it runs the Cocoa event loop).

Please only give performance tuning advice if you have a thorough understanding of the topic and you can show some empirical data.

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I agree that setting ‘Run as Administrator’ for all users is potentially unsafe.

I recommend only setting ‘Run as Administrator’ for the relatively secure access point of your account, if you understand the risks etc.

SC is recognized by the Windows OS as being from an unknown publisher, and by choosing this option means you are informing the system that the app is safe to run.

I also cannot… exactly, verify that the following is true:

Run as Admin → Better Performance
Set Priority +1 → Better Performance

I can only attest that through my observation & personal experience, it only seems that SC runs faster, and crashes less, when adjusted this way.

Do what thou wilt.

Ok, I did a quick test with Process Explorer and I have to correct myself somewhat: raising the priority in Process Explorer raises the priority of all threads with a lower priority.

By default, the network thread and NRT thread have a base priority of 8 and the audio thread has a priority of 15. After manually raising the priority to “High (13)”, the network thread and NRT thread have a priority of 13, but the audio thread still has a priority of 15. This means that the audio thread is not really affected. However, it is a legit question why the network and NRT thread should run at “Normal” priority. I think it should be possible to raise the priority as long as the audio thread still has the highest priority.

@Rainer I am wondering what you mean exactly when you say that after manually raising the thread priority SC seems to run faster. Audio computation can’t be affected, as I have shown. The only things that could run faster is dispatching of OSC messages/bundles (possibly allowing for a smaller Server latency) and execution of asynchronous commands. But for both we would need actual empirical data.

In the meantime, I would appreciate it if you could add a disclaimer to your original post. Your advice to run SC as administrator is certainly bogus and the advice to manually raise the thread priority at least questionable.

Generally, the rule number one for performance tuning is: measure!

Alrite C. & thanks for the schooling.

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@Rainer thanks for the edit! Very much appreciated :slight_smile:

Hi! Just signed up to the forums to ask the experts about particulars, like limiting factors on windows, and fixes :crossed_fingers:t2:

I’ve just read your excellent remark(s) here whilst looking for related :information_source: on
best sc windows performance config :ok_hand:t2: and wondered if there’s anything already in this forum that I should review.

Currently on hp laptop windows 10 (native vhd on SSD FWIW)
with 16gb RAM
builtin realtek audio (problem a?)

using sc via sonicpi, looking at reported latency, in addition to attempting to overcome timing issues when running particularly fast songs, like this:

Jumping off point: Resynthesis by Max Cooper - Creations & Ideas - in_thread (

I’m also asking in the sp thread to see if this works for anyone on any windows, but assuming it’s the (sc) engine under the sp_hood that’s unable to handle the speed of the synth calls that determines how fast a performance can be played, and how many synth calls can be made before inevitable failure (to mitigate/pre-empt) I’d love to know what’s known, or believed, re: best possible config, and requirements to achieve these goals…

Am willing to run tests, purchase new hardware, whatever it takes!

Thanks in advance! Back to the hunt (for wisdom :mage:t2: )