DVS Glitching and not keeping perfect time.

Hi,

I am starting to use DVS on my XDJ XZ and I get glitching fairly regularly, particularly when in the mix. I also find the timing isn't great - certainly not perfectly in time, even when using BPM sync.

I have a dedicated Macbook (2017 i7 3.5GHZ, 16MB) which should handle this easily and shows no signs of being stretched. I have disabled WiFi and closed all other programmes.

My turntables (1210's) have recently been serviced so should be fine.

I have routed the XZ into the Macbook via a USB hub which also has power going into it.

I have tried adjusting the sample rate too.

Still glitches and is unusable. 

Help graciously received!