High DSP load

In the past I mainly used RENOISE native stuff. Now I want to use much more plugins, but something is strange here:

I recently bought HIVE from U-he, which is very light on the CPU. Loading 10 instances in Reaper makes the DSP load increase to ~2%. When I load 10 instances in Renoise I get a DSP load of ~30%! The same I observe with other plugins. Does anybody know why is this the case? I always thought Renoise is very efficient.

Hi, if you are using the plugin bridge, try without it (requires restart of Renoise). Also AFAIK Renoise’s cpu meter shows the current maximum peak of one core, for example you are using a heavy load, only single core using VSTi (e.g. Falcon), it can already show nearly 100%, but you still then can add many other instances of Falcon, which will use another core. Maybe Reaper shows the average cpu load (I don’t exactly know). That said, if a plugin is causing such high cpu peaks, it is a sign of bad optimization, maybe even denormal number behaviour.

Hi, thanks. I made some tests again and Reaper processes the audio in advance, that’s why it’s more efficient. Here’s a thread I started at linuxmusicians:


I was wrong about the 2%, it seems to be ~12% in Reaper vs ~50 in Renoise. The DSP load shown in Cadence (i.e. Jack) is an average value. The maximum can be much higher. I get xruns at values of ~60 % Jack DSP load sometimes indicating, that the peak is >80%.