Hello, I own 3 samsung evo 850 500gb ssd's. They are awesome. If you compare an upgrade from hdd and ssd you will tell a difference. But comparing 2 nice ssd you will not tell a difference in real world performance. Samsung has nicer perks, Sandisk has a tiny more horse power but no difference. I would buy the cheaper one and spend the rest of your money on a better graphics card or something.