I'm using ios 7.1.2 in my jailbroken iPod 5.
And yes, i noticed that just running tonestack together with mididesigner greatly slows down the speed. I cannot find any setings in tonestack that improve the situation.
Running mididesigner with only loopy also slows down the speed, but less than with tonestack. Loopy clearly states its midi connections, and only the mididesigner midi input is selected. The reduced speed is noticable is loopy as well as in midi designer.
I'm off to a 2 week holiday tomorrow do any further testing wil have to wait.
Cheers,
Tom