Lord ram is different from lord krishna because Shri ram does not know he is an avatar of Vishnu, while Krishna does know. Shri ram is considered as 7th avatar of Vishnu and Krishna as 8th avatar.
For devotees of Krishna, he is the greatest even; the complete avatar (poorna avatar), the most perfect personal manifestation (suguna Brahman) of the impersonal divine (Nirguna Brahman).
In some parts, for many devotees, krishna's heaven of goloka stands higher than lord vishnu's vaikunta. Vaikunta is located in the "ocean of milk", but all the milk comes from the udders of cows located in goloka. These cows voluntarily release their milk because they are so moved by the music of shri krishna, inspired by the beauty and love of radha rani.
Krishna plays the flute as he stands under the celestial kadamba tree which in goloka takes the form of kalpavriksha, the divine wish fulfilling tree.