Latency suddenly appears after ~3 minutes

[CZFred]

Strange one this...

Using a MOTU 828ES, Windows 10, in a CUBase 10.5pro project with only one track, and no effects, and no other tracks, and no weird routing or effects anywhere. I.e. as basic as it can possibly be: Using a AKAI MPK261 to play the (any) MIDI instrument on that track, all is fine, with no detectable latency (between me pressing the keys and hearing the sounds) for a 2-4 minutes. Then I'll hear a slight buzz-type sound from the main outs and/or headphone, after which there's then 0.3 seconds of latency from that moment onwards: Enough to make it unplayable.

This happens with the MOTU connected to the PC with Thunderbolt and it happens when it's connected to the PC with USB. It happens with the keyboard connected with DIN MIDIs (to the MOTU) and it happens just the same with the Keys connected to the PC with USB. All four combos of these - it happens.

It also happens in any and all CUBase projects.

Closing the project and reopening it, or opening another one, does not resolve it.

Closing CUBase and reopening it DOES resolve it - but only for another few minutes 'til it happens all over again.

If I take the MOTU out of the equation, and use the Windows ASIO Low Latency driver (instead of MOTU ASIO pro (the latest version), the problem goes away completely and never returns - even after an hour or more of playing.

Back to using the MOTU: If I wait for it to happen (using the MOTU ASIO pro driver and the MOTU 828ES), I can resolve it by going into CUBase Studio settings and changing the ASIO driver to the windows one, or to no driver (and 'saving' this by clicking okay) and then going to Studio again and changing it straight back to the MOTU ASIO driver. But then it comes back after the 3-4 minutes.

At no point does my CPU or disk or RAM ever get anywhere above 20%. It's a powerful computer.

So, another test.. ..To eliminate CuBase from the puzzle, I used Kontakt player to play a drum. Exactly the same thing happens. After about 3-4 minutes, the little 'digital noise'/buzz followed immediately by 3rd/sec latency. Solution is the same, change the ASIO driver to the windows one, and back again, and the latency is gone for another 3-4 minutes, then repeat!! GRRRR.

I also think that there's no issue with MIDI data getting IN from my controller keyboard - as the little MIDI 'light' on Kontakt has no latency. But the sound (and the meters on the 828ES) are delayed by the 0.3 seconds or so.

Finally - and sadly - this effects audio too. I recorded the click track in cubase and my finger clicks before and after the problem starts, and the recorded clicks are on the beat, then, once the problem happens, they're then 0.3ish seconds after the beat on the recorded track. The input meters on the MOTU respond with no latency before and after - so, just like with the MIDI, there's no delays in getting the audio/data IN. But it gets processed late. Help!

Maybe this extra information will help one of you experts.

Any ideas anyone?

Thanks,

Fred