I've used the Play Store to look for apps and according to the developer's description, those two apps have the same meaning, but run on different devices:
Clean Master x86 is developed exclusively for devices that are running on Intel CPUs. It won't install or run on normal Android phones with Snapdragon CPUs, for example.
Clean Master Lite is developed to be installed on phones with less than 1 GB of memory. The software is using modules that are low on memory while keeping performance an cleaning the phone accurately.