Thankfully, you have lots of options that bring a noticeable effect. If you see registry cleaner performance tests, they are probably phony and either made up by the company or someone getting paid to sell one. Since registry cleaners are automated, there’s a good chance that their registry scan could tag something as unnecessary when it’s actually important. And unless you’re a registry expert and check every entry before deleting them, you could cause major damage to your system by deleting something inadvertently. BCD.dat (in the \boot folder in the system partition) which is a critical file that the system…