I've said this many times, but those later Omegas (500 series onwards) have finer pivots are are more susceptible to suffering from the effects of dirty jewels as there is less torque going through the train.
However, you mentioned it runs fast, so I would also look very closely at the action of the hairspring to look for any irregularities. Could be bent or magnetised.
Is the amplitude the same DU and DD?