That has nothing to do with why the iphone is so fast.
Civilian transmission rates on L1 are 10x slower than the military L2 frequency. It takes a full 6 seconds to get a single frame downloaded and that is also hoping your almanac is up to date. (Thankfully AGPS can provide the almanac data by other menas.)
The military version it takes .6 seconds to do the same it takes us civilians to do in 6 seconds. The SA drift is gone now but still the slower speed makes fixing a perfect position slightly more difficult and less accurate.
