I tested it with ipython:
```
In [1]: x = np.random.rand(4096, 4096) + 1j * np.random.rand(4096, 4096)

In [2]: %timeit np.fft.fft(x)
1 loops, best of 3: 649 ms per loop

In [3]: %timeit (np.fft.fft(x) / 1)
1 loops, best of 3: 894 ms per loop
```
That's a big increase, I'll do separate calls.