I have just updated Synthmaster Player to its latest version and now performance is awful with Multi-Processing turned on, at buffers 256 and lower.
Nothing better than a video to show you guys, you won’t believe what’s the fix to this.
As we can see at a buffer of 512 everything runs smoothly, but as soon as I set the buffer size to 265, the audio starts dropping out and the performance meter goes crazy. The dropouts are more intense at lower buffers.
When I tweak the core affinity for the Cubase.exe process, the issue goes away instantly. If I tweak the buffer size afterward (or reset the audio engine by any mean, for example inserting/removing a plugin), the dropouts come back again. Afterward, tweaking the core affinity fixes it once again.
We can also notice that when Cubase is in the glitched state, the dropouts are even more prominent the fewer cores are selected, but even then, tweaking the core affinity to as low as 2 cores still fixes it and permits an almost flawless operation (there’s just a few dropouts here and there because I was at lowest buffer, but only 2 cores isn’t very stable either).
Also note that tweaking the core affinity can be done at random and in any direction in order to fix the glitch, not just going down starting from core 0. You can still check back all core and it will fix it until next time the audio engine is reset.
It seems like Cubase is sending the instructions erratically and is having a hard time to synchronize the tasks between all of the cores. Tweaking the core affinity seems to rearrange the instructions and synchronize everything properly.
When we disable Multi-Processing in Cubase settings, the dropouts do not occur anymore and we do not need to tweak the core affinity any longer.
This is exactly the same issue as the one with Spitfire that I have discovered earlier, as the fix is the same. This would definitely prove that this very specific bug originates from either Cubase or VST. And I’d rather opt for VST because Cubase itself is VST-based, and the Multi-Processing option actually controls how the whole VST system behaves (Cubase AND plugins).
Some people will start saying this is not the appropriate topic to post this… But it concerns the Multi-Processing option and would indicate the presence of an even more severe underlying issue which is the one that was discussed in all the posts above.
How do you guys explain that when this glitch is occuring I have all cores loaded evenly (prior to tweaking the core affinity), and after reducing Cubase.exe core count from eight to 2 or 3, the glitch goes away and now only 2 or 3 cores are loaded instead of all 8 cores, which greatly reduces the global usage?
Of course if we lower the core count we won’t be able to work on large projects nor reach a high polyphony count, but still what kind of weirdness is that?
We are on to something very serious once again but I have a feeling this will continue to be ignored by the developers.