Hey mahri726,
If you are going to be designing a game for the Mobile/HTML 5 platform, then you should be able to switch to the correct preview rendering level and whenever you restart your project the setting should not need recompiling. I tested this on my end and saw the initial recompile of shaders, but after restarting it switch over to Mobile/HTML 5 preview rendering level without recompiling.
If you are trying to get performance back when running on a lower end computer, you can use the Engine Scalability Settings to set the engine rendering settings to low. This will reduce the overall quality of your game, but also give back some of the performance.
Let me know if you have further questions.
Cheers,