I get decent A/C when I first start driving, then about 10 minutes in it's like someone hits a switch and the fan and compressor boost into overdrive and start pumping out serious air velocity and coolness. Anyone echo this?

 

not sure if mine does this, but it might just be that it waits till the engine gets up to a good operating temp. before the AC goes 100%

 

My '06 997.1 does something similar, I think after it settles down, It goes to recirculate and speeds up the fan. If you have auto-climate as I have, that's what I attribute it to.

 

It sounds "normal" to me. It would take a while for the pressure to build after a cold start. Once the car is ready, it tries to get to your set temperature as fast as possible. If in doubt, change the temperature (up if it's hot out) to see if the fan slows down. If it does, you know the system is reacting properly to environmental conditions as it should.