Computer processing (low framerate):If your computer does not meet the minimum system requirements, you will probably experience slowed gameplay. When playing Minecraft, press F3 to view information about the game. Look at the top row and locate the FPS. If this number is lower than 30, the game may be running too slowly due to your software configuration or insufficient graphical and computer processing hardware.
Network connection (latency or lag):This is usually caused by a slow or inconsistent internet connection, or by a slow server. In general, the information is not going between your computer and the server that you're playing on as quickly as it needs. While Minecraft may perform similarly to the issue above, your framerate may not always be low, and you may experience characters "jumping" from location to location as the server and computer catch up with what should be located where. If you're experiencing slowed performance due to a connection, you may need to pause or stop any current downloads, change your network settings, or you may require a faster internet connection.