From my understanding this feature does not use both Wi-Fi and cellular simultaneously to "boost" download speeds. The ability to jump to the cellular network when Wi-Fi signals are too weak (again in my understanding), is intended to reduce or eliminate timeouts and data interruptions or fragmented/slow webpage loading. If the "Boost" feature is a "hidden " feature it would be advantageous mostly for downloads.What's kind of funny is the S5 has Download booster which is a little toggle that you could turn it on it would use WIFI and data at the same to download quicker . The kicker is Verzon removed that option form the Verizon s5's . And here we are it's a hidden option on our Turbos.