Autotune 7 64bit on Cubase 7 64bit (Mac)

I’m getting heavy cpu spikes with AT 7.6.7 64bit in Cubase 64bit (Mac OSX). The playback “stops” including the cursor’s movement but the program does not crash. It’s more like very slowly responding without any audio coming out.

It seems to be related to the time tracking function. When I tune-track only it works flawless.

Anyone else?