Because of prior disagreements between Google and Amazon, the Chromecast and the Firestick run on different casting protocols. This scenario means that compatibility issues between Chrome and the Firestick occur. If you are getting choppy streaming, it may be because of that incompatibility. You may also be experiencing lag due to slow internet speeds or lack of bandwidth. Check if other devices are using your internet connection. It could be an ISP problem and you're not the only one experiencing slow connection speeds.