270x Pros: will be faster
Its newer
Full dx 12 features
will handle games better
Mantle
Cons: will use 70 more watts and runs 1-3c hotter
650 ti boost pros: will use less power, will run a little cooler,physx
cons: slower, older, 2 generations behind,
Now note both cards can use physx but the 650 ti has a better advantage
In this case the 270x is a better choice in overall