CPU spikes

i7 2600k - win 7 64 bit - 16gb RAM - Cubase 6.0.5

I only recently noticed that Cubase is causing quite large spikes on core 1, even on an empty project. After a lot of forum and net trawls, I decided to disable hyperthreading in the BIOS, but no change there.

Using Task Manager, Resouce Monitor and Process Explorer, the only thing I’ve been able to find is that System Interrupts are the problem. It spikes at around 60% cpu on Core 1 around every 5 seconds. However, I’ve not been able to figure out why this is happening. I tried to install the Windows Development Toolkit to further analyse, but that install consistently fails for some reason.

To confirm - the problem goes away with Cubase is closed. Also checked with Sonar 8.5.3, and that is clean.

All suggestions gratefully received - thanks.

Dongle/eLicenser traffic…?

Interesting theory - how can I tell? Nothing showing up as a process or service…

I don’t think that you can. E-licenser traffic would originate (I think) from a function call from within Cubase. Wouldn’t create a new process.

Staying with the fuction call theory, could be system timestamp (however, I would think that this would be a lot quicker than 5 seconds [if it causes a CPU spike at all]).

It also could just be windows doing something related to Cubase in the background.
It could be anything, really.

In your original post, you said that you found that System Interrupts were at fault. Did you pinpoint this to a specific process in task manager (assuming, as you did not say, that the spike did not happen within Cubase’s process)?

Do you have multiprocessing turned on?

Not really a good comparison. Different DAWs can be programmed radically different.

Have you turned on the Steinberg power scheme? I know this won’t get rid of the spike, but it will avoid the constant fluctuations in processor core frequency.

Regarding the spikes themselves, are you running Cubase with an active wifi connection?
Has your motherboard got Bluetooth and is it enabled?


Thanks folks, appreciate the ideas and questions.

Steinberg Power Scheme was off. I just tested it on, and as you said, it doesn’t seem to make any difference to the spikes. Didn’t seem to change the core distribution (at rest, anyway).

No wifi on board, or bluetooth.

System interrupts - no, I couldn’t tie in any process at all. When it spikes, Cubase sits there unaffected - as does everything else. But if I close Cubase, the System Interrupts stop.

Multiprocessing is on.

The purpose of the Sonar check was to see if something common such as ASIO drivers might be causing it, but it doesn’t appear so.


Is the spike consistent in nature, i.e. every exact 5 seconds (I saw you said around that interval), or does it vary, like in 3-7 seconds, etc.?
What audio device are you using?
Do you have a lot of USB/FW devices?

It’s slightly irregular - here’s a screen shot of a couple of minute’s worth CPU usage on core 1, no other programs running. Each vertical line represents 5 secs I think.
Cubase CPU spikes.PNG
Audio device is the M Audio Fast Track Pro.

No USB / firewire drives connected.

I don’t think that looks unreasonable for one core.

BTW, I did not mean just USB/FW drives, but ANY devices, mouse, keyboards, additional dongles, etc.

Really?!! That’s spiking at 60%. Doesn’t spike at all with Sonar. This is normal? I think not…

Other devices - there’s a 4 way hub for the dongles, the keyboard, the soundcard… not sure there’s much else tbh.

Plug the cubase dongle directly into a USB port on your computer.

When I load C6.5 with no loading and look at Task Manager Performance Tab the 8 CPU graphs (hyperthreading on) are all at the very bottom of the graph.

So it’s unlikely that it’s cubase that’s causing the spiking.

Thanks for the idea - was worth a shot, but no change. Tried a port at the front and the back.

I did not imply that it’s normal, merely reasonable activity for a single core in a multi-core system.

If you close down Cubase, what does System Interrupts show in the CPU column (in the Resource Monitor) then?

Split and Elektrobolt - I’ve always presumed this was a problem that isn’t universal. I think we’d all have heard about it if everyone’s rig spiked constantly on one core @60-70%! So it’s definitely something that isn’t a universal problem (and thanks for confirming that, Elktrobolt).

As expected, the System Interrupt shows 0% when Cubase is closed (indeed, it shortly vanishes from the service list completely after closure). To confirm - the spiking behaviour ONLY manifests when Cubase is open, but the Cubase process does not itself spike.


A few people have pointed me at the eLicenser as a possible culprit. I suddenly thought - a ha, I have VSL libraries on there too. So as another diagnostic check, I tried the VSL standalone player. And sure enough - the spikes are back! So that confirms that this is an eLicenser related issue. That’s as far as I’ve got - don’t know how universal it is, whether or not it’s a 64 bit issue.


It’s a VSL issue.
As you have said, when you close Cubase, the spikes disappear. When you open VSL standalone, the spikes reappear. The e-licenser is just going to sit there idle until a program throws a system interrupt to ask if a specific license is present.

Both of these seem to indicate that Cubase isn’t at fault. I don’t think Cubase checks for the presence of its license all that often (based upon other threads in this forum that I’ve read).
VSL, however, could check for its license every five seconds.

Different programming methods.

IF you want to really nail this sucker down, you might want to try this:
(Instructions for advanced system drilling cannot be easier than this.)

By using this tool kit:
(I prefer using the VS 2010 Diagnostic Tool because NO installation is necessary, just extract and locate the tool.)

This will give you what is going on over a period of time. You can run it several time to compare situations.

It’s not logical to me that it could be a VSL issue. The spiking behaviour is identical if the Vienna Player is open, OR a blank Cubase project is open - with no plugins of any developer at all. The common link is the eLicenser. To me, that’s a pretty definitive diagnosis - it’s neither Cubase or VSL per se, but something to do with the licenser. It doesn’t follow that anyone else will have this issue, only that I do.

I’ve no idea how frequently either checks for the presence of the dongle - I can see how it would be relevant, but I wouldn’t be totally sure that that would be the issue.

I’ve just installed the latest version of the eLicenser software, and done the maintenance checks. No change to the spiking.

Elektrobolt - I should have said in the OP, I’ve actually run the DPC Latency Checker. It reports a clean bill of health when the spiking is occuring. I did try the SDTK, but the install constantly fails for some reason (it doesn’t give a reason, just suggests to contact them).

EDIT - off to bed. Really appreciate the help folks and grateful for all ideas. I’ll be right back on it first thing in the morning!

Cubase will cause a CPU spike when it checks for its license on the e-licenser. However, Cubase doesn’t check that often. So this doesn’t explain the frequency.

As per Split’s post:
"When I load C6.5 with no loading and look at Task Manager Performance Tab the 8 CPU graphs (hyperthreading on) are all at the very bottom of the graph.

So it’s unlikely that it’s cubase that’s causing the spiking."

What we don’t know is whether or not he has VSL.

Unless somehow Cubase is triggering VSL to check for its license at startup.

Based upon the behavior of Steinberg’s trial VSTs that come with Cubase (Halion Sonic, HSO Vst Set, The Grand SE [again, from threads I’ve read]), it’ll check for licenses for VSTs at startup (since these VSTs throw errors at startup if their license has expired).

VSL could then stay partially active and keep checking for its license.
You can’t tell if VSL is active, because it’ll be hidden within Cubase’s process.