Cubase Pro 11 CPU & GPU usage vs Task manager

Can someone please explain to me why my Cubase project shows audio performance maxed out to the red, with frequent processing overloads and drop-outs, when Task manager indicates Cubase is using only CPU 36%, GPU 20%, and RAM 22% … and total load of all processes is CPU 60%?

Why is Cubase not using more of the available resources?

I have buffer at 2048, and multi-processing and ASIO guard enabled.

Drop-outs seem to get worse any time I use the UI - eg. drag a fader or open a plugin window during playback. Surely Cubase can handle this?

thanks.

EDIT: I have 64 Gb Ram installed. I use VST3 plugins where available.

I have the same problem

Simply said: Cubase computes all plugins of one channel in one compute thread and thus on one CPU core. If that one core is saturated, the Cubase meter goes into red and you experience dropouts.
This can happen if you have a lot of CPU intensive plugin on one channel, say u-he DIVA as an instrument and then several plugins on the inserts, maybe an amp sim or so.
You can see that in the task manager if you switch the CPU graph to “logical processors” (I think, right click on the graph and see what’s there…).
You can also test it yourself:

  • create a new project
  • create a new audio track and load several of your most CPU consuming plugins and watch how Cubases’ meter climbs. (compare with task manager)
  • now duplicate that track. The audio performance meter should’nt actually increase much.
  • repeat the process until suddenly the meter jumps a big step. You’ll notice that you now have one more channel than the number of logical processors on your CPU.

Solution: Don’t use too many resource hungry plugins on one channel. If you cannot avoid that, the only solution I know is to create a group track and route the channel to it and split the plugins across both channel.

btw: if task manager says that Cubase is using 36% but all processes together 60%, that is not good. It could actually be that there is another program running that hogs much of one CPU, and that can lead to problems, too.
The whole system processor usage should not be much higher than that of Cubase.

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Thank you for this excellent response!

Makes sense.

So audio performance meter should really be labelled “compute thread congestion”?
The audio drop-out warning message should say “try dividing heavy channels”?
And maybe I should not leave a heavy channel selected, because Cubase will work harder to try to reduce latency on that channel?

I will do the post-processing group trick.

VSTi freeze helps too. But I tend to use it as a last resort because (1) Cubase does not allow batch freezing of instruments/channels, and doing them one-by-one is tedious (2) it’s unreliable re-loading plugins on unfreeze (eg. Omnisphere outputs are forgotten)