Try running it from the start screen instead. Running from Visual Studio in 'debug' mode reduces performance, and it's faster once you publish.
Just to confirm Ashley's response.
That is what you have to do. It will not run properly from VS. You need to run your game from VS, then close it. Now you can run it from the Start menu- without the stuttering.
Same is true if you run your game using the simulator. With that you need to run it using the simulator. Close the app from VS but keep the simulator running. Then close VS itself. The simulator will still be running. Now you can use the simulator to access everything on the start menu including your game. (the simulator still runs a bit daggy even after that but noticeably better)
Note: to close the simulator you have to do the same as you would to shut down your PC.