4 GB minimum; 8 GB is highly recommended for a smooth experience.
The most secure way to get this version is through the official Android Studio Download Archives . android studio 2.3.3 download for windows 7 64 bit
You must have Java Development Kit (JDK) 7 or 8 installed on your system. 4 GB minimum; 8 GB is highly recommended
Advanced design tools for building responsive user interfaces. 4 GB minimum
Intel or AMD with virtualization support (Intel VT-x or AMD-V) is required if you plan to use the Android Emulator. Key Features of Version 2.3.3
Early support for Android 8.0 (API level 26). Installation Steps on Windows 7 Android Studio download archives - Android Developers