Compute shader textures compared 2D float4 arrays
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.