1.37Vcore @ 4.0Ghz speed is my dream    very low temp there. aircond room? 
corsair dorminator is a 
you can increase the fsb so the cpu-nb will increase as well. its the best if you can get the proc at
3.6Ghz above and the cpu-nb clock near 2600Mhz    ram @ 1600 CL9 is ok edy.

this is stupid question i think, which one good, mix Corsair 2x4GB + Kingston 2x1GB total 10GB or just use corsair 2x4GB total 8GB only?

its run dual channel even if i mix this 2 pair 
u want buy my Kingston? 

the ram speed + cpu-nb speed will increase when you increase the fsb a.k.a HTT
the purpose of lowering the ram divider is to achieve higher proc clock 
so the ram wouldn't be the culprit of any unstable issue because oredy know your ram limit
if not in the aircond room then your system has a very low temp there 
just use 2 identical ram --> 4GbX2 Corsair