Notice that the second timing below is "0 seconds", which is clearly completely wrong.
The notation "3r" means the unpreparsed 3, i.e., the Python *integer* 3. There
is a *noticeable amount of time* that passes when the input is given. So something
is very very wrong. This happens on intel os x and on 64-bit opteron linux (and
probably all other os's).
sage: time n=int(3)**int(999999)
CPU times: user 0.76 s, sys: 0.00 s, total: 0.76 s
Wall time: 0.76
sage: time n= 3r ** 999999r
CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s
Wall time: 0.00
sage: preparse('time n= 3r ** 999999r')
'time n= 3 ** 999999'
sage: preparse('time n=int(3)**int(999999)')
'time n=int(Integer(3))**int(Integer(999999))'