the intervals fluctuate betweenn 998 and 1010 milliseconds on my computer.
i tried it with my internal soundcard as well as my focusrite saffire pro 10 wich doesn't make any difference.
i have scheduler in overdrive turned on and in audiointerrupt.
nothing running except this little patch above and safari.
i'm on mac osx 10.5.7 and max5.0.7
i have a unibody MBP from may 2009 with 2,4ghz CPU, 2gb ram, 250gb HDD and a 256mb GPU.