666? then its not gkx.... gkx doesnt scale above cas5...
the difference from 555 to 666 is maybe 2mhz or so :P
so yeah try running 1300 555, if its gkx it should work, but seeing as they seem to scale with trp and trcd set to even 7(!) i doubt this is micron based mem...

maybe its promos? must be really well handpicked promos tho...

612.6Mhz CL6-7-7-31-2T@2.45v
thats it? 1225 677? i thought they are rated for 1300 666 with 2.45v?

maybe your board cant run that high memclocks?
what board does team recommend?