The installer is roughly 528 MB , and you will need at least 2 GB of free disk space for installation. System Requirements for Legacy 32-Bit Unity
Click on the Unity 5 tab to see all legacy versions. Choose a Compatible Version: Unity 3d 32 Bit Download Free
While 1GB is the bare minimum, 4GB of RAM is strongly recommended to handle the Unity Editor and an IDE like MonoDevelop simultaneously. Graphics: DX10 (Shader Model 4.0) capable GPU. Important Tips for 32-Bit Users Unity download archive The installer is roughly 528 MB , and