VST Performance meter spiking? Try the Core Affinity trick

Only for multiple core users!

I know this is an old trick, but I didn’t find any fully detailed instructions so that it would also save the settings. Seems to be working for me with Win 7 64bit and C7 64bit. Most of the spikes are history. I have 8 cores and want to use all but the first (Core 0) with Cubase. So I made Cubase always start with these cores only.

You can change the affinity by Ctrl+Alt+Delete -> Task Manager -> Processes. Right-click cubase7.exe and Set Affinity. However, the settings are not saved.

Here’s how you can save the affinity settings:

  1. Right-click Cubase 7-shortcut from your desktop. Choose Properties - Shortcut.
  2. Clear the Target-field and paste the following (quotation marks also!)->

"C:\Windows\System32\cmd.exe /c start “Cubase7.exe” /affinity XX “C:\Program Files\Steinberg\Cubase 7\Cubase7.exe”

  1. If your Cubase isn’t in the default folder, edit the above text.
  2. You need to replace the XX with a correct hexadecimal number. To calculate the hexa, first you’ll need a binary number. Decide what cores you want to use. Go to http://www.mathsisfun.com/binary-decimal-hexadecimal-converter.html (or other binary to hexa-calculator). Type the cores backwards to the binary field, 1 to use it, 0 for not. For example I don’t use Core 0, but use all the rest, I will type 11111110.
  3. Replace the XX in the shortcut Target-field pasted text with the hexadecimal number showing in the calculator. For me it’s FE.
  4. Start Cubase and check the affinity from the Task Manager.

I hope it works for you too.

Addition: If you are pushing your computer to the limit and don’t want to disable a core, you can actually put the affinity right back when you have launched Cubase. At least I didn’t notice any difference with spikes. However, this cannot be done automatically. But if you have a fast computer with many cores, no need to toggle the core back with lighter projects.

I still read almost daily about ASIO-meter spiking and I’m bit surprised no one has commented anything to this thread. Is there any drawbacks I might not know or is everybody already using this?

Very interesting post.
I myself am on C7 - mac, so your story can’t be done on mac (AFAIK).
Maybe offtopic but i like to know if the stories about the fact that macs can’t handle core synchronisation as well as windows does is are really true.

From what i understand, good core synchronisation is crucial for good asio performance.
The more cores your CPU has, the more CPU resources it will take to get the core’s perfect synchronized.

I dont understand how switching off 1 core for Cubase improves performance?

Just tested it though and it really does improve performance, thanks for the tip! Still wonder why tho

Initially, I reasoned this that the first core is where everything else is, Windows, browsers, your porn videos, etc. So there might be some conflict between Windows and Cubase and that causes problems. But you can put the disabled core back and everything will be fine, so that indicates it’s something else. Maybe Cubase somehow gets the priority this way, I don’t know… So I don’t quite understand it either, but if it works, it works.

I want to emphasize that this trick is not my invention and it’s known at least from the days of Cubase 5. That indicates the problem is something to do with Windows. If it was from Steinberg side, I think they would have fixed this during the YEARS.

But what the hell, test it. If it doesn’t work, you have lost 10 seconds of your time. But if you do see an improvement, then use the steps described in the OP to make it automatic, and you have gained something.

Been using it and it has led to about 20% improvement :laughing:

If you guys want to add a little automation to your affinities you may find this useful.

I wrote it a way back when it was almost essential in order to get the UAD running well with Cubendo.

Info here:


The tool was written in 2009.

Auto Affinity Tool - Phil Pendlebury

At the moment there are some known problems with Cubase / Certain OS / UAD2 cards etc. that require Multi Processing to be turned off within Cubase.

The other way around this is to disable CPU 0 affinity and then re-enable it again.
For me this has to be done after Cubase has started - It does not work if Cubase is started with CPU 0 affinity OFF (I tried this also using command line).

I have written a little application that will do this in one click.

You must set Task Manager to show Processes tab and the Cubase process must be visible. You only need to do that once.

Download the zip file
Unzip and put the folder anywhere
Make a short cut to the auto_affinity.exe file
Put that shortcut anywhere you like that is convenient.

Edit the “autoaffinity.ini” file so that it shows your audio application exactly how it is written in Task Manager.
For example (default):


Another example:


You may also need to edit the following, if you are using a language other than English.
The name of your Task manager Window
def_taskmanagername=Windows Task Manager

The name of your Processor Affinity Dialog
def_processoraffinityname=Processor Affinity

Which processor you want to turn on and off (0 = default)

When you have started Cubase / Nuendo click the shortcut. (Task Manager must be closed)

If audio application is not started the app will open task manager and do nothing.

You should see (very quickly) the Task manager open and Cubase task selected - CPU Affinity will open - Disable and re-enable CPU 0 affinity.

Much quicker than doing it manually.

I have found that I need to run this AFTER a new project is loaded and if ASIO buffer sizes are changed.

I hope this may be of some small help for some people.

Download (original version) here:


Here is a slightly modified version that works with Windows 7. I have to use Arrow Keys and Spacebar to get to the processor. This may also help some poeple who were having problems with the other version not running correctly. Also this version will check and if the TM is already open it will not stall.

Download new (Windows 7 / Alternative version) here:


I don’t use this any more at all but it may still be useful. For support please use the quoted thread if required.


Are you guys using Hyperthreading?

Initially, I reasoned this that the first core is where everything else is, Windows, browsers, your porn videos, etc

thanks for the tip. now i affiniate my porn videos :smiley:

actually i was advised several years ago on Gear Slutz forums to do so with C5. dont even remember if it worked !

good reminder !

Well just tested it.
for me best works when i Disable cores i think they are the emulated cores (don’t remember the actual name)
on my I7 mobile CPU.
win7 64b - C7 64b

i took it to the limit until it was spiking all the time and when disabling does cores it improved the Asio performance by 15-20 % :stuck_out_tongue:

as for hyper threading i think i cant disable it on my Sony Vaio laptop. not from BIOS anyway :unamused:

interesting. Will have to give it a go if there’s still the problem after the fixes in C7.0.2 (have rolled-back to 6 to keep working in the meantime)
Thanks so much. It gives me something to try that i haven’t already. Had never heard of this, so thanks again :slight_smile: