Compute shader textures compared 2D float4 arrays I am wondering is there a difference in performance between using floating point textures as my 2D float4 array vs just passing in 2D float4 arrays? 

2D float arrays eliminate the need to do texture look ups to get the colour value, but i am not sure if perhaps textures have some kinda performance boost on GPUs that an array would not due to what ever clever optimisations GPUs can do.
It depends on what you’re doing. If any given thread of your shader is working with data from multiple nearby pixels, like by sampling from fractional between-pixel locations or doing some calculation involving a pixel’s immediate neighbors, then you should probably use a texture: the GPU can do some caching and even load multiple values in a single operation in that case. If your threads are more independent and working on individual values, an array is fine.