CPU usage, internal vs. VEPRO


I’ve tried playing the same piece with VSL Synchron Player directly inserted in a VST Instrument slot, and run inside VEPRO7.

When inserted in a VSTi in Dorico, the requested resources are much higher, and there are several spikes. The sound is often interrupted.

In VEPRO, everything runs smooth. Despite the only VI playing is in VEPRO, however, I see the VST Audio Engine task running a more than 100% in the Mac’s Activity Monitor.


VE Pro adds a second layer of buffering, so make sure you account for that when comparing the two environments.

But in general, I also find VE Pro to better manage CPU resources.

Dbudde, I’ve left VEPRO at the default settings (that should be the double buffer is active). If this makes CPU performances better, is there a way to do the same in Dorico?

I also did another comparison by letting Logic play a midi file exported from Dorico, with exactly the same virtual instrument. While Dorico was making my overall User CPU rate jump to about 50%, Logic only goes up to 13%. During playback, Logic is demanding 34% or my CPU, while Dorico + VST Audio Engine was over 200%.

Two different programs, so not really comparable. But I wonder if there is room for improvements in playback. (Maybe the aforementioned buffer could be an option).

By the way: the CPU Meter in Synchron Player shows very different numbers when running directly in Dorico, or when running in Logic or VEPRO (with Logic and VEPRO showing similar numbers).


I haven’t done much experimenting with Dorico’s engine because it was unreliable for so long until recently. So I don’t have any data. But you might try to match the total buffer time (e.g., if VE Pro has two buffers each set to 256, then make Dorico’s single buffer 512).

OK, that’s it. I had Dorico’s buffer set to 256, as I had in Logic. VEPRO Server has double buffer in both cases. But Dorico requires more buffer memory, so I increased it to 1024. Now, it works fine, with no audio cut. Synchron Player shows a much lower CPU use.

Still, Dorico + VST Audio Engine take over 200% of my CPU while playing.