Z87 - Sabertooth & GSKILL XMP issues

[chetanzcool]

Just got a new Rig built .

Core i5 4670K
2 x GSKILL - F3-12800CL9S-4GBXL Also tried 4 x GSKILL - F3-12800CL10-8GBXL
BIOS - 1205
Z87 Sabertooth

Everything works absolutely fine at Stock.
Everything works fine Overclocking CPU all the way to 4.5 GHz (1.22 V V Core)
But if I simply enable XMP , the system wont post at all , the RED LED will stay on and then overclocking failure post screen comes up.

Thought it must be a RAM problem and got a replacement GSKILL - F3-12800CL10-8GBXL

Tried Single DIMM in each slot but the second I turn XMP on the system fails to post.

http://www.gskill.com/en/configurato...307&model=1406

I am pretty frustrated with this. Any clues , Beta BIOS .....similar experiences, RMA ?

[Tradesman]

XMP only works by the packaged set, with single sticks, will work as a single, but not whaen adding additional