There's only one doubt to be removed; supercool your cpu/nb and see if you still fail linx, then you'd be able to tell if it's heat/voltage or a timing issue. Linx will stress your (total) system more than MCI memtest ever could. As you can see from the ss you provided, your cpu isn't working as hard. With linx all your components are operating at full power, even the integrity of your power supply comes into play.