time.time vs. timeit.timeit

timeit is more accurate, for three reasons:

• it repeats the tests many times to eliminate the influence of other tasks on your machine, such as disk flushing and OS scheduling.
• it disables the garbage collector to prevent that process from skewing the results by scheduling a collection run at an inopportune moment.
• it picks the most accurate timer for your OS, time.time or time.clock in Python 2 and time.perf_counter() on Python 3. See timeit.default_timer.