Plugin CPU usage

I finally went ahead and bought SynthMaster. In Reaper, loading the plugin and punching keys on the MIDI keyboard (no recording) uses 2-3% of the CPU. In Renoise, it is 30%. Using three instances of the plugin and playing three tracks with simple notes (MIDI tracks) and no added effects, gets me at 41% load in Renoise and 7% in Reaper. The presets are the same in all cases. With six instances, it’s 48% vs 10%. 64-bit versions of both DAWs and the plugin.

I feel like I’m overlooking something that is probably terribly obvious and that I really should know, but I’m drawing a blank here. Why is the CPU load in Renoise (with this plugin) so much higher than in Reaper?

(Five minutes later). Actually, the CPU usage display in Renoise doesn’t reflect the CPU usage shown in Windows’ Performance Manager (which shows 10% when Renoise’s CPU meter peaks a 48%). Multicore support (8) is enabled. The CPU is an i7-3610QM at 2.3Ghz. Is it just an issue with the CPU meter?

This is a frequently asked question on the forums, and it’d be worth your time to check out similar threads to understand how Renoise processes audio with multi core processors.

Thanks, I did a bit of reading now, chiefly:

Hmm, this is both confusing and a little useless for how I use the CPU meter, but I’m used to Reaper’s way of displaying usage (which seems to reflect the performance manager’s display, which is the actual CPU load).

I’m glad it’s not actually a problem and Renoise isn’t hogging the CPU. :)

Actually the Renoise CPU meter could be improved. Like showing max peak and also current real usage. For all cores. So a graphic approach like logic etc. and a CPU meter mode for the mixer view where I can see a percentage on every plugin + generators. Or a graph over time from all plugins, so I easily can see which plugin produces high peaks and causes problems. With a denormal numbers detection. With a chart like this: Graph example

And of course a value showing how much the CPU meter is using ;)


I sleep pretty badly the last years, so I maybe have forgot that you already explained this to me:

What was the Renoise cpu meter actually showing again? Is it the maximum peak value of all cores together added, or the maximum of all cores’ peak value? Or is it an average value?

So if I use a VSTi which doesn’t support multicore on its own, let’s say Falcon 2 (great free update btw.), and one instance uses 90% of cpu in the Renoise meter, is it then still possible that I could have almost “100% cpu” amount left with another Falcon instance on another track, so not seeing the actual possible free cpu time?

:smile: Thanks.

On my system (windows 10) it looks like it is the overall CPU usage of all cores, it shows similar percentages like the CPU monitor of the operating system (overall CPU usage in task manager). I have set Renoise to use all cores.

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