Samsung Galaxy S3 has a 4.8″ 720p display. It also was the first device to have a quad-core Exynos 4412 processor, with each core clocked at a maximum 1.4 GHz. It packs NFC, wireless charging capability, and the latest wireless radios. It ships with Samsung’s Nature UX interface. At the time of its launch, it ran on Android 4.0.4 ICS.
The Galaxy S3 is almost 3 years old now so Samsung has stopped the official support for this device. However the guys of the CyanogenMod team have continued their work for this device and have come with CM 12.1 ROM for this device. It will update the S3 to Android 5.1 and bring along the CyanogenMod goodies. Follow the guide below to install it on the S3.