I don't think so... you could compare this to Max/MSP or other audio applications.
In my experience using jack imposes additional load, since it will be just another layer between the application and coreaudio.
14.7% 14.7% mach_kernel ml_set_interrupts_enabled
12.3% 12.3% AudioToolbox Resampler2::ConvertAltivec_SmallIntegerRatio(float*, float*, unsigned long, int)
6.1% 6.1% com.apple.driver.AppleHDA SInt16ToFloat32
5.0% 5.0% com.apple.driver.DspFuncLib DspFuncOrgEQ::_EQBoth(float*, float*, unsigned long, unsigned long)
3.5% 3.5% mach_kernel lo_mach_scall
1.9% 1.9% com.apple.driver.DspFuncLib DspFuncVolume::process(unsigned long, unsigned long)
1.4% 1.4% mach_kernel mutex_lock
1.2% 1.2% CoreAudio IOA_Time::GetCurrentTime(AudioTimeStamp&) const
1.2% 1.2% mach_kernel lo_alltraps
1.1% 1.1% IOKit iokit_user_client_trap
1.1% 1.1% commpage [libSystem.B.dylib] __spin_lock
1.1% 1.1% CoreAudio AUGenericOutputEntry
1.0% 1.0% libSystem.B.dylib semaphore_timedwait_signal_trap
0.9% 0.9% libSystem.B.dylib semaphore_wait_trap
0.9% 0.9% libSystem.B.dylib _pthread_cond_wait
0.9% 0.9% commpage [libSystem.B.dylib] __nanotime
0.9% 0.9% mach_kernel mutex_unlock
0.8% 0.8% commpage [libSystem.B.dylib] __memcpy
0.7% 0.7% mach_kernel lck_mtx_lock
0.7% 0.7% AudioToolbox Resampler2::PushConvert(float*, float*, float*, float*, unsigned long&, unsigned long&, unsigned long, unsigned long)