Could also just be outages in your area, new towers, etcetera will all effect those speed tests, stuff like software updates doesn't usually lower speeds, though i have heard a lot of complaints after updating (on other phones) about losing connection/reception
Sent from my LG-D950 using XDA Premium 4 mobile app
XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality. Are you a developer?