try this....
First enable Enable load line calibration and retest, vdroop could be your problem...if it still fails then try the following

CPU Clock Skew : Delay 100ps

CPU GTL Reference 0 : -40mv
CPU GTL Reference 1 : Auto
CPU GTL Reference 2 : -40mv
CPU GTL Reference 3 : Auto

If its still crapping out you will need more PLL or vcore