If you search for my username in that thread I asked for someone to run the code from the story on a similar dataset with PyPy. Twice as fast but x10 memory usage. But as I said elsewhere a bit of searching suggests it won't be a showstopper.
Be careful extrapolating from such small examples, where the memory usage is dominated by fixed overhead. Running Django or something similar is more likely to give a real world result, and even then, a bunch of tests is far better.
3mb vs 30mb might be par for the course for smaller programs, but either is negligible.
