Lower than HarmonyOS system 3. The running memory occupied by HarmonyOS System 3.0 is different on different memory models, and the running memory occupied is 2-5GB. Shortly after the release of HarmonyOS System 4.0, the official did not release the specific data of running memory occupation. According to Huawei's official introduction, HarmonyOS System 4.0 adopts distributed technology to make better use of equipment resources and improve system performance and operating efficiency. Compared with version 3.0 and before, it can save 50% memory occupation and be more optimized and streamlined.