Clicking latency on input signals- any ideas why?

[andrew.scandal]

Hi,
I am running Live Suite 9.1.5 on Mac 10.9.4. 2.6 GHz 8 GB ram
When I am listening to audio signals going in, there is both a latency and a regular "dropping" of the signal.
This would happen before, but after I ran Live for a bit, it seemed to "warm up" so to speak, and it would stop. Now it won't.
For instance, if I sing "ahhhh" into the mic, the sound I hear is "cut up" at regular intervals, "ah-ah-ah-ah-ah" and it repeats at the end too.
It's like there is a delay or a gate on it, but the signal is clean. You can hear the click- it is at a regular tempo, but is not the metronome or anything like that. Even when the track is not playing, I can hear it through my headphones clicking on the ambient noise of the microphone. There is some regular latency/delay occurring in the background.
I'm trying to sing over backing tracks (which play normally without issue), but the tracks being auditioned "live" are so cut-up and delayed, it's currently impossible.
I'm using a Focusrite Scarlett 8i6, Core Audio, the buffer size is 256 samples, and driver error compensation is -7.00ms. But none of these things were issues before.
The same happens on an instrument if I plug it in. Basically all input signals are being delayed and cut up, like a gate/delay is on it.
Any ideas?
Thank you,
Andrew