OK I did the benchmark
Device: Zynthian with RPi 3 / Hifiberry
Software: Mod-Ui + ZynAddSubFX (Preset Hyper Organ 1)
Input Chain: PC with Ableton -USB> Sound Card (Steinberg UR22) -MIDI> Zynthian
Output Chain: Zynthian -Jack> Sound Card (UR22) -USB> PC with Ableton
Thats quite a long input chain but I wanted to use Ableton for MIDI input in order to make sure that the input does not depend on Human timing. On the other Hand we have now to keep in mind, that the latency shown in the data below is the result of the whole input and output chain.
First run: Zynthians default settings (44100Hz)
23.9% CPU load. Thats why I have chosen this patch: It has a good punch on the CPU without being a problem at 44100Hz)
Thats a 40ms latency of my input/output chain - for my personal taste this is a bit to much.
Second run: Now with 48000Hz
CPU load 26.4. Of cause CPU load is not perfectly steady but it does not vary that much and I tried to take the screenshots at an average level.
Latency is similar to 44100Hz.
Third run: Lets take it to 96000Hz
50.3% and going into red alert mode. I have tried other patches and reached higher CPU load values but reached only in rare cases the red alert.
Uh whats that! ~33ms - lets try again -> OK its repeatable. Too bad that it is too hard for the Pi`s CPU.
For now I will stick to the 48000Hz. There seems to be no advantage for the latency but it is just increasing a little bit the CPU-load and according to Wikipedia:
48000Hz: The standard audio sampling rate used by professional digital video equipment ...