I tried the values you recommended but it didn't work either. However, please note that the behavior of the buffer delay control is strange. For example, when I go to the Axe-Fx MIDI I/O tab, the advanced section lets me change the MIDI buffer size but the delay control beneath (Axe-Fx II USB) is sometimes greyed out, and other times I can change the value. I'm not sure what controls this feature? When I am able to change the buffer delay value then that value does not get remembered since if I exit the dialog and re-enter it the delay value is back to zero and greyed out. Note that the buffer size control does remember its value after re-entering the settings dialog. Weird!Can you change those values to 128/90 and see if that makes a difference ?