That's true, cache utilization declines as a function of your processing parallel (and in gunicorn/celery, your max-requests-per-process-before-suicide setting). Cached properties still can help a good deal though, especially when coupled with a) careful prefork initialization of cached data and b) even more careful use of multiprocessing's little-known shared memory interface which really does allow caches to be shared, without read locks, between multiple processes.