CPU usage on iOS device

Hi, I’m currently developing iOS app using OfxPd (Openframeworks and libpd).

When running my app on iPad2, the cpu usage reached about 70% with only drawing 16 rectangles that act as buttons.
This was done with no object running in pd. which means only OF was using CPU.

After adding pd objects for drum sounds, the CPU usage reached about 95~105%.
But strangely, I couldn’t hear any crackling noise in sound which normally happens when CPU usage gets high enough.

When I was developing app with iOS & libpd and no openframeworks, the crackling noise already happened when CPU usage reaches around 80%.

So, I tried to see when this crackling noise happens with OfxPd.
I duplicated some pd objects to boost CPU usage, and I found out when CPU usage reaches around 130%, I could hear the crackling noise.

How can it exceed 100% and still run well?
And what’s the meaning of showing its limit around 130%?

crackling noise is probably due to you not outputting audio samples fast enough. Your audio DSP is taking too long to process. 130% means you are using 2 cpus. Graphics and audio are done on two separate threads