Best option for better Mac Os Performance

Hello, I need to install Windows on my Mac, but I have no need to to boot it directly, so using Parallels virtual machine will be my way to access it. I'm aware that when using both OS at the same time with parallels the performance slows down a bit because the system divides the hardware for both OS. The question is what's the best alternative to do the installation of Windows and keep the best performance of my Mac OS when I'm not using Windows or parallels: Install Windows on Boot Camp and create a Virtual Machine of it or Install it directly on Mac OS creating a Guest OS Virtual Drive? I have already done the second option and noticed that my Mac Os is slower than usual do boot and do some tasks. By the way, I have only 4GB of RAM. Thanks

 

Thanks, PaulChris! It really improved the overall performance os my Virtual Machine!! But considering I want to install Windows for the first Time on my Mac and have no need to do a separate boot, what's the best option to slow down my Mac OS as little as possible: Install Windows on a different partition via Boot Camp or install It directly on Mac OS via Parallels?