not that im really interested in benchmarks, but does the 25% difference for file rendering as well? again, the problem with mac rt-sound (although seemed ok on a G3 i tried out yesterday) is that its not done the most "proper"(low-level) way, and i have a feeling the newer OSs/Compilers also have made additional need for more tweaking -- but we really need to rewrite/replace all the real-time code... (well, Csound itself probably needs a rewrite [SAOL??]) matt --- "Ross Bencina" wrote: called GetNextEvent() or similar every processing loop (or atleast sometimes) to allow background processing.