you might want to decrease your multipyer and start increasing your BCLK
I have a 930 with BCLK of 200 and multiplyer of 21 giving me an OC of 4.2Ghz.
I know i can go higher (watercooled as my CPU temp never goes above 70DegC with Linx but just no time to muck with it.
to many voltages to fiddle with. not enough time to adjust each one.