Excess persistent CPU Usage - Windows 11

I am seeing excessive and persistent CPU usage by VST Live when playing a VST instrument via a midi controller. I have replicated this with a new project with a single VST instrument loaded into a single layer in one song. I am running on an i7 11 Gen processor with 16GB RAM on Windows 11.

A short while after I start playing (typically 5 - 15 seconds but this varies), the CPU usage jumps to 25% - 30% and remains there. The CPU frequency also raises to 100% and remains there. When I stop playing, CPU usage remains at the same level indefinitely. As soon as I close VST live, the CPU usage stops.

I have replicated this behaviour with several different plug-ins, including Addictive Keys, Blue3, Keyscape and Zenology. It only happens after I start playing. I’ve tried to isolate it further but I can’t find an exact trigger such as duration of playing or number of notes sustained.

This issue is killing the battery life of my laptop and keeping the fans on full blast whilst VST Live is open. Using Cubase , Ableton or standalone VST instruments does not do this. The battery lasts 3 times as long even when using Omnisphere as opposed to VST Live.

Here are screenshots, showing
1 - start,

22 seconds in (having starting playing at 15 seconds )

30 seconds in - the CPU usage increased on 22 seconds and remains high

90 seconds in - having stopped playing after 45 seconds. CPU still high

105 seconds, having closed the project after 90 seconds.

I should also add that I have replicated this using two different audio interfaces, a Steinberg UR22C and an Arturia Minifuse 1.

It does not appear to be related to audio performance at all. What you show is the system monitor, while (as far as is visible) the VST Live CPU meter stays perfectly calm.

Works fine here with a similar setup. It must be a pecularity of either your system setup (background services, programs running in parallel), or more likely MIDI related issues.

It would be good to know if you have the plugins’ editor opened.
Can you enforce the same behaviour with built-in Instruments? If so, you could send us a simple .vlprj file showing the problem, thanks!

Tried Addictive Keys Demo and could not observe any of what you did.
Maybe you are chasing ghosts? Don’t get me wrong, don’t want to claim that there is no problem, but if all goes well - why worry?
There is a slight increase of CPU when playing notes. That is to be expected though, because the real work for any synth starts when sound needs to be produced. However that is also reflected in the CPU meter in VST Live.

Thanks for such a prompt response. Re chasing ghosts, this is an issue for me. It has a real impact in excessive battery usage. When using VST Live, a full charge can be exhausted inside of an hour. When I use Ableton, I can get more than 3 hours. This is the difference between needing to plug in the charger for gigs or running on battery. Plugged in is not always practical and can introduce noise into the sound if the venue mains isnt 100% perfect. It also drives my laptop fans 100% of the time, again making more noise on stage. If I don’t find a resolution, it may force me to abandon VST Live, which would be a great shame. It does so much right. So I’m motivated to try and find a fix.

I noticed that the CPU usage for the VST Live process is not showing anything. However, no visible process is showing any CPU either but the overall CPU usage is visible. I will look into this, see if I can figure it whether there is a hidden process using the CPU or whether something is not getting tracked properly by the Windows resource monitor. I’m not going to bet on which just yet.

It is most definitely linked to VST Live in some way, as it requires VST live to trigger it, it remains forever whilst VST Live is running and stops immediately when the VST Live application closes.

I’m not sure about the MIDI drivers. I get the same issue no matter which keyboard I try, my Roland RD-88, my Casio S500 or my Roland A-pro 800.

I don’t think the issue is a plugin, as I can replicate with any plugin. I will have a go with a built in instrument as you suggest and let you know. I will also do some more testing in the next couple of days. Won’t be today, as am out at band practice after work. Will try and eliminate as many other running processes as possible, stick on flight mode etc.

For reference, my day job is software dev and solution architecture. Whilst I don’t have any audio dev experience, I’ve a reasonable understanding of Windows development. I’m a bit rusty but should be able to get some debugging tools up and running that may give me some more clues.

I’m sure there is some issue somewhere that we can resolve. It isn’t just a normal use pattern.

Cheers for your help.

Wondering what impact it could ever have - this makes sense. Although I’d never enter stage on battery only :slight_smile: But you posted some good reasons.

I would however never expect low power consumption with any audio processing software, unless it is quite a simple setup with very few plugins running.
But again it looks like we’re not even talking about audio in the first place.

Then you should understand how it works: for every audio buffer, each active plugin is a) passed MIDI events if any, and b) its audio processing procedure is called. Plugins are blackboxes, and VST Live does nothing fancy or different from other VST hosts.

This is because you said the behaviour is based on MIDI events beeing fed to the instrument. I cannot observe any of what you described, CPU does raise when notes have to be processed with pretty much every instrument, however it also does drop down to its previous level once the sound has entirely been processed. Note the Layer Sustain preference, which keeps the plugin busy until all notes (and sustain pedal) are released, and that time has passed (tail).

If you change to another Song (prefereably with no active plugin), does it drop at all?

Maybe this helps to narrow the cause. Thanks for reporting, we want to make it as performant and safe as possible, and maybe this will help.

I’ve repeated the tests using Halion Sonic 7 and I get the same issue. I’ve attached the project file. I’ve also included a video. I have opened the project and start playing at 10 seconds till 40 seconds.
This shows Windows Task manager performance monitor has VST live holding CPU usage even though nothing is registering on the CPU meter in VST Live. Changing songs and parts doesn’t change.

Looking at the CPU graph, one thread , CPU 2, is shown rising to 40% 3 seconds after I start playing. dropping to 30% and remaining there after playing stops on 40 seconds., till I exit the program at the end. I literally don’t touch anything for 30 seconds before switching to song 2 and playing for a few seconds. I then leave everything alone again for another 30 seconds. CPU2 stops running the moment I close VST Live. I can leave this 30 seconds or 30 minutes, it doesn’t matter (except my video would be very large and very boring).

It is as if some task is getting assigned its own thread and then left running. It never stops till the application is terminated. It fluctuates when I play part 2, dropping fractionally below 30 but then remains above 30 aside from a couple of brief fluctuations again.

I’m out of time tonight, but will test again tomorrow and put the midi monitor on. I want to confirm whether any midi is still transmitting.

Perf Test.zip (13.3 KB)
ok, here is the project file. It won’t let me upload the video, I will have to grab screenshots later.

I can somehow reproduce something…will check and get back, thanks!

We are forever grateful!
There was a flaw in the MIDI Input thread (MME; may not apply to Mac). It would not stop spinning, once an event was received.
Obviously, this will be fixed with the upcoming release. Note to other users reading this who might be concerned: it does not usually have any impact but unnecessary calculations, which cause power consumption.
Thank you once more!


Great news. I wasn’t a million miles away in guessing what a possible cause may be. I’m glad I was able to help out. Good to catch these things before they become a serious issue.

I’m trying to work out if you have been up all night fixing this,based on timings of your posts. I hope I’ve not been depriving you of sleep.

Anyway, I’ll let you get back to adding new features. Keep up the good work.

I can confirm that this is now fixed in v1.2.3. My CPU sits around 7% and the clock frequency never goes past 75%. Previously CPU was jumping to 30% and clock frequency 100%.
It is nice to see just how efficient VST Live is running now. A world better than Ableton!