I suppose its possible that a 512 stick would clock easier...but still, that's asking a lot out of 2.8v. The best I know of anyone doing at such voltage is ozzimark...he did a suicide at 530 3-4-3. A 1M bench at 552 I suppose is barely within the realm of possibility, but I echo the general response in this thread and say that some extra proof should be included with such an achievement. Nothing against the OP in the slightest, just that such claims should have some concrete backup regardless of who's posting.

Yoxxy's suggestion is a very good one. CAS 3 pi results are untouchable by CAS 4 at the same speeds.