On Xs there's noone recorded here with that batch... these are the only 813's listed

Q813A199 4Ghz 1.32 Vcore
Q813A499 4Ghz 1.28 Vcore
Q813A518 4.3Ghz 1.33 Vcore

Try PLL at 1.5 and FSB Term at 1.2... if not stable try PLL 1.6 and FSB Term 1.2, if not stable 1.6 and 1.3