Latency issues

I’m using:
OSX Yosemite | 3.4GHz | 32gb RAM 27" Late 2013
Apollo 8 Thunderbolt 2, Logic X

Been testing the Analog 4 in the studio, simply running it through Overbridge within Logic via USB - Latest software (and Analog 4 OS) installed. But been getting quite a bit of latency, I’m quite new to hardware and have only started connecting via USB to try the software within logic.

Audio settings: I/O Buffer 256 | Latency 18.7ms (6.3) | Delay -18 | Threads: 4 | Buffer: Large | Multi: Playback & Live | Rewire: Off | Compensation: Audio and Software.

I find theres quite a delay at times during playback, and hoping someone might just spot something that needs changed. What I havent changed, is the settings in Overbridge itself. The margin is at 100 and Buffer set to 64.

The latency problems is from playing a single sound also, and a few soft synths in Logic itself.

Thanks in advance!