Trust me, pitch shifting ALWAYS will have latency, or else it will sound like complete garbage. It's impossible to pitch shift without running a bit of the signal through the algorithm so it can figure out what to do with it.

If it was real time, it would literally not work at all.

I swear they said they killed off a lot of latency though. In a video with Rob Chappers, a Line 6 rep said they have 0 latency, but I guess that's not the issue. I was skeptical myself, because like I said, pitch shifting will ALWAYS need latency.

It does NOT matter if your processor was the speed of light, a processor can't see into the future, so it needs a bit of the signal to calculate the pitch.

Remember, pitch = frequency = time, ergo it needs time to calculate.

example:

./¯¯¯\........./

/.........\___/

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That's a sine wave, the width represents the pitch, as it does represent time. You need time to read the wave, ergo it needs 9 MilliSeconds to see the whole pitch. The longer the latency, the cleaner the tracking, but we usually deal with a short frequency range, so we don't need the latency to be that high.

In short, Processing power will not help the latency.

Also someone mentioned that if your audio interface is having latency, that will tax even more latency onto everything.