Android Lollipop is the biggest update since Android ICS was released more than 3 years ago. It changed a lot of things – from UI to features to runtime and much more. It improved the performance of the device due to the ART and also animations are much more smooth now. In spite of this, you can improve the speed and performance of Android 5.0 device.
XDA developer Paget96 has created a L Speed mod which will increase the speed, performance and even improve the battery life performance. The L Speed mod works on any device and ROM. But clean up your init.d folder before flashing. A detailed guide is given below.