Mobile operating systems are very lightweight so that the mobiles hardware can easily support the operating system and apps running on it. Some operating systems include additional features like sensor embedding and OTG aka On-The-Go. In this paper, we are going to focus on the performance of heavy applications running on both Android and iOS platforms and their processing delay causes. The performance testing is done with the help of a cloud testing platform i.e. bitbar.cloud. It is basically testing as a service provider which tests the Android and iOS applications with the help of simulated virtual mobile phones which uses Appcrawler and AI Testbot for testing these applications. The file packages need to be uploaded on the cloud platform which should be in the form of .apk and .ipa extension. The uploaded files are then tested by using either AI Testbot or Appcrawler by creating a new test in the Test Run Creator. With the results generated by these methods, we will compare the performance of these heavy applications on the different and their performance delays on the different devices and their underlying operating systems.