I'm using it with Pro Tools 12 on a fairly moderately spec'd Mac - i5 processor, (24GB RAM for what it's worth) and can only use with a 256 sample buffer! Any thing lower has terrible clicks and pops, with the CPU maxing out easily. To compare, I tried using with GarageBand (latest version) as don't have Logic X or any other DAW, whilst I don't know the buffer size of GarageBand uses and seems theres no way to check or change, it feels okay to play (and no clicks or pops). In PT12 at 256 samples, it feels almost unplayable for me with input monitoring (using a pretty fast Thunderbolt interface too), GarageBand, not so much. All this considered (as well as being the only track and only plugin being used on either DAW), maybe this is a Pro Tools specific bug/problem? Any other PT users able to comment?