On Mac OS X, Pd is using the double precision math functions even though Pd uses single precision floats. You can see it here:
http://pure-data.cvs.sourceforge.net/pure-data/pd/src/x_arithmetic.c?view=markup
Here's a previous discussion on this:
http://lists.puredata.info/pipermail/pd-dev/2006-01/006042.html
I don't think this would make a massive difference overall, but I'll bet it would make a significant difference for any patch using sin, cos, atan, atan2, sqrt, log, exp, fabs, or pow.
Anonymous
it would be interesting if you could do some benchmarks...