Using parfor for many expensive lsqcurvefit

Hello,

I am trying to parallelize my fitting code for the first time. I am running several hundred fits using a computationally expensive fitting function that takes a few seconds for each fit. As a test I set up a simple code but found that using either for or parfor the code took the same amount of time for any number of fits. What am I doing wrong?

        clear all
        close all

        nu = 200:2:800;

        beta = [1.5, 1.3, 520, 1, 0];
        beta0 = [2, 2, 521, 1, 0];

        intensity = ModelFcn(beta,nu);

         betaTest = zeros(4,5);
         parfor iTest = 1:4

         betaTest(iTest,:) = lsqcurvefit(@ModelFcn,beta0,nu,intensity,[0 0 0 0 0],[5 5 600 2 1]);

         end