Originally Posted by
Looking4MoreFun
Each operator has its own strategy but in general you will be pushed to 4G if available. The phone with check signal strength and quality continously and push you to 3G if you pass these thresholds.
A good tip is to try a speed test on 4G and then lock to 3G in the same location and see what the difference is. Sometimes signal can be strong but due to capacity on the cell you made have reduction in throughout. For browsing download speeds and latency would be good metrics to watch.