There is the compute vs communicate ratio.

For problems like Matrix Multiplication, it costs N to communicate the problem but N^2 operations to calculate.

For problems like dot product, it costs N to communicate but only N operations to calculate.

Compute must be substantially larger than communication costs if you hope to see any benefits. Asymptotic differences obviously help, but linear too might help.

You'd never transfer N data to perform a log(n) binary search for example. At that point communication dominates.