Finally got a OnePlus One... Need advice

I had then zenfone 2 with 4GB of ram... It ran great but for gaming it ran like crap... I don't think they are optimizing games with Intel chips yet... So I found someone who had a 64GB Oneplus One and we traded phones... Great deal as I love this phone and I can do with 3GB of ram... Now my question is CM12.1 latest update the best this phone has to offer or is there better ones out there.. I game a lot and I mean a lot lol... Like modern Combat 5 GTA (all of them) and mortal Kombat X for example... Also anything I must do besides root my device and unlock bootloader (that's always obvious lol) thanks guys for your help and advice...