i try to find the best way to use ofelia/gem graphics without audio drop-outs.
increasing latency did not help a lot.
then I tried to optimize the patch, that helped a bit.
then i tried the [pd~] subprocess method, which worked well for [readsf~] but not for more complex sound synthesis.
what i like about the subprocess is that the main patch can start the subprocess automatically and without gui.
there is also no problem with connecting and disconnecting the ports after reopening the patch...
but the best solution i found (without any dropouts) is to have two seperate pd instances and send data with [netsend].
it works well with sending 3x256 values 60 times a second.
to simulate the automatic start process from [pd~] i tried this, but somehow it crashes pd

i wonder if there is a way to start a second instance from in pd (the best case with opening a certain patch) without crashing.
and i wonder if i miss something about [pd~] because for me it seems much slower then [netsend].

@Jona I have had no luck with [sys-gui] .... same object in principle I think..... opening a second instance correctly from a patch. The first instance, making the call, always loses focus and is effectively crashed until the second is closed again.
Two new instances can be opened cleanly by executing a batch file through [sys-gui]...... but there is no advantage over executing the batch file directly, as again you leave your first patch hanging.

start "path...... /pd.exe" start "path.... patch.pd"
start "path...... /pd.exe" start "path.... patch.pd"
exit

will do it, and any startup flags can be added to pd.exe to set all the specific parameters you might need for each instance....... while Pd will be back to your normal setup when you open it again later for "normal use".
I always use batch files with switches to open Pd for a show, as there is then absolutely no doubt that it has opened as intended.

As I understand things Windows distributes instances across cores automatically.
In theory you could set the affinity....... start -affinity 3F "path...... /pd.exe"....... but maybe you would need to use pd.exe for one instance and pd.com for the other. Not sure about that.

David.

@whale-av thanks. I think I will use a batch file then. And I also think that [sys_gui] has the same functionality...

@Jona motex/system seems to allow both instances while hcs/sys_gui appears to suspends the calling instance until the second instance is closed
two-pd.pd

@balwyn that is interesting (so there is a mechanism to start the second instance correctly). but somehow motex [system] does not work for me at all.
and ofelias pdSysGui seems to have the same behaviour as [sysgui].

I found this on my harddrive. By Katja. It woks with pd-extended. Somehow a fast atempt with Pd-0.49-1-i386 did not show any success after changing the path in the .tcl.
EDIT: im on OSX 10.11.6. after looking at the .tcl file from katja, i could imagine a way with [shell] in the same manner.