I've been using this interface for 5 years with no noticeable issue so far.
I remember I had to struggle at the beginning to get the right settings.
I finally found something that works well for me : depth=24bits, sample rate=44100Hz, buffers=256ms.
I've found that all the settings should match either in the Motu Audio Console, Reaper preferences and sound properties in Windows.
Reaper runs on a Windows 10 PC in a very standard way which is not dedicated to music production (but with a lot or ram).
I don't know wether you have connected your Motu via USB or Firewire. I connected mine with USB2, and I remember that I had to try the connection with all my USB2 ports until I was satisfied (and I've got 8...).
And while the fact is well known, remember to disable all the applications and services that are running in the background (antivirus, cloud sync, energy management, etc.).
All in all, I'm very satisfied with this interface. It's very versatile and sounds good. The ability to record and mix live situations is simply amazing in such a small unit. CueMix is very useful and the effects are quite good (comp, eq, reverb). I don't need anymore to connect my synths to a table mixer for live playing. And I LOVE the possibility to connect a good preamp with Spdif without sacrifing the other inputs.
A final thought : maybe a clean reinstall of the driver could be useful.
Hope that helps!