pmp, try different FSB straps.
I've just finished the testing for the Gigabyte GA-EP45-DS5 review at stock conditions, and I can reach Performance Level 4 stable, 3 is impossible ( instant crash ).
The Asus P5K3 Deluxe ( P35 ) can reach P.L. 3 stable at the same settings, [b]however the performance is the same. We can say that P45 PL = P35 PL + 1, at least under 350MHz.
Don't know when I'll do the testing required to start the overclocked measurements.

The results for stock ( they're directly comparable with the results of the Asus Striker II Extreme review & the Gigabyte EP35-DS4 reviews ):