Your system reads like the ideal MIR-setup, so it takes me by surprise that you have any problems at all. I will do a test later today on my system (which has less RAM, though).
Just to be sure - you experience these glitches as soon as you switch from the Instrument Channel to the Output Channel view? As long as you see the Instrument Channel, the same project is doing fine? Does it help when you increase either the system-wide latency settings of the RME Control Panle, or MIR's dedicated Buffer Multiplier?
Does this happen with less instruments, too?
And you are sure that this happend with older builds, too?
BTW - what is the graphics card of your system?
@Ramu said:
[...] Hope this could help you, First Officer! ;)
;-D ... at least _one_ person who read the manual from cover to cover!
/Dietz - Vienna Symphonic Library