Sync Issues with Hardware Synth

I’ve been having some issues getting my Virus C to sync up with the Cubase transport.

I’m not using any external Midi Clock, would that help with sync? Or is the internal Midi Clock in Cubase good enough?

I don’t think it’s a latency problem as sometimes it works perfectly on time, sometimes not. However I always have to have the track record enabled (or with the monitor button on) to make sure the sync doesn’t go COMPLETELY off.

It is quite subtle, however it’s obvious enough to have to keep bouncing out the Virus to use it in a track.

Has anyone found a way to rule out any sync issues with their hardware?