Help with Auto Tune Evo in Garageband!

I just had to upgrade from Auto Tune 5 to Auto Tune Evo (because of Snow Leopard). Now I am experiencing latency when I record. Is there any way to reduce this back to real time, or am I screwed? It doesn't even do well when I'm not using it in real time. I'm using a Digidesign Mbox Mini as my interface. Please help!