Have you tried more nb voltage ? where you at now with nb ? cause 1.4s aint going to crack it, it takes me 1.56 to hold my 2040 mghz, my gues is you need at least 1.54, that could be the problem with why 4 gigs goes but 8 dont, you have watercooling right ? im on air at 1.56, and fine, up the nb, cause i know if i drop to 1.54, wont run at all, i get dram error on lcd poster.