Every computer is different in terms of its ability to handle the tasks involved in making it a music studio.

You have the option of avoiding listening to the signal post (after) it has traversed the computer, by opting to monitor the MOXF "Direct". This means you will be listening to the MOXF connection directly from the instrument to your sound system. When recording to a computer based system you are creating two audio streams - the normal one direct to your speakers and the USB signal that travels to the computer before it goes to the MOXF (acting as your audio interface).

"VST Play" is the routing scenario that disconnects direct Monitoring and allows you to listen to the audio that has been routed through the computer, it is the latent signal... If your Buffer Size is more than 10ms this can be noticeable, unless you are processing signal with a plugin effect and need to hear this latent signal, I would opt to monitor "direct". Direct is zero latency because you are listening to your instrument normally.

You don't mention what type of computer your using... But just FYI, you often can reduce the latency by optimizing your settings.

The latency does not matter on playback - it matters when you are in an overdub situation (some are playing back while you record). This is where monitoring direct can make recording smooth (zero latency). Cubase will automatically place your data so that when you playback everything is spot on.

Thanks a lot.
I used to keep buffer size to 128.
The problem started when I upgraded to the last driver's version.
By default it switched back to 512.
Putting it back to 128 I fixed the problem
Thanks once more.
Your service makes the difference when choosing Yamaha between other brands.