This is true for mLAN devices like the Yamaha 01X. If you are using the 01X or another mLAN device, try setting the MOTU Audio System’s Work Priority to Medium or Low (found under the Setup menu > Configure Audio System > Configure Hardware Driver). When using a Low or Medium Work Priority, increase the Buffer Size for the best results.
Usually when using any MOTU audio interface, PCI or FireWire, set the Work Priority to High. Most interfaces by other companies will also use the High setting.
The exception to this are users with slower single processor computers, who may benefit from changing the MAS Work Priority to Medium. This include such machines as early PowerBooks or a G4 single 733 MHz desktop.
If you are having issues with audio playback, such as your audio is glitching and/or the processor is spiking with a low track count, try changing the MAS Thread Priority to Medium or Low.