Macbook Pro USB Guitar Sound Issue
You're never going to get zero latency. The amount of latency you do get will depend on buffer size, which should be settable in either the driver or your audio app's control panel. The smaller the buffer, the greater the processing power needed to achieve it, hence the breakup as you reduce it. 

Investigate using any app that can use ASIO rather than the system drivers, &amp; don't run any unnecessary apps at the same time.