some testing on review sites have shown that Sata 2 and Sata 3 ports did not make much difference in real life usage even though their theortical differences are high because there aren't many applications that work to the max theoretical speed of Sata 3.
U will probably not notice much difference Sata 2 and 3 in
1) older computers (bottlenecks eg. CPU, ram)
2) normal usage eg. web browsing
3) don't constantly engage in copy and write file operation eg, running a server