A
Taken the words right from my mouth, well keyboard but anyway this is true. Performance apps are anything but. They use your resources, constantly run in the background and more than a few are nefarious and actually push you or try to scare you into downloading other less than beneficiary apps. The same for anti virus apps. Keep up on your cache cleaning, restart your device every few days and you'll find that your performance will increase or at least not diminish. Also be aware of what you download on your device. Low rated apps can cause issues as well so always read reviews before installing.Without knowing the specifics about what kind of performance you're talking about, there isn't much else to say, except: The best way to improve performance on Android is to not install any apps that claim to increase performance.
Seriously, most of those apps do more harm than good. Some are ok, but avoid anything claiming to speed up the phone by clearing memory.