Question: Multi-threaded parallel programming a nested for loop

I have a nested for loop that iterates through a range of values for x and y coordinates to create a 3d surface for illustration of my research. after the x loop there is a y loop, and inside of that y loop is a series of commands to find some eigenvalues of a matrix (which become the z coordinates) and sort them into already open files. This isn't bad when the precision i require is more than .02, but some of my matrices require up to 0.005 or less. The latter precision costs hours of computation time on just one processor. However my laptop has an i7, so I want to see if i can get the for loop to send its next iteration to the next processor in line while it has the previous ones still calculating. Have any tips?