The answer may depend on what you mean by fastest. If you're simply looking for the baler that can cover the most ground in a given amount of time, then it's probably going to be a large-frame model with a wide pickup. However, if you're talking about the baler that can produce the most bales per hour, then it's likely going to be a high-capacity machine with an extra-wide pickup and high bale density settings. In either case, your best bet is to talk to your local John Deere dealer and ask for their recommendations.