Lag

Please attach the complete output of the "Development console" which can be found on the second tab of the launcher.

If the launcher closes after game start, please edit your profile and select "Launcher visibility" then, "Keep the launcher open".

Please force a crash by pressing F3 + C for 10 seconds while in-game and attach the crash report ([minecraft/crash-reports/crash-<DATE>-client.txt|http://hopper.minecraft.net/help/finding-minecraft-data-folder]) here.