Has anyone tried running memory in all 4 slots (not necessarily at the same time) above 820mhz?

I've just installed 4x1gb of Crucial Ballistix, but one of the slots (DDRII2/left-hand red one) refuses to budge over 820mhz

The other three slots will all let me boot all four sticks at 1000mhz.

I'm not even sure if that's grounds for RMA considering that the spec only goes as high as ddr2-800.