Corsair XMS2 800mhz overclocking problem

Hey guys, My system setup is the following :

Asus P5B
C2D E6600
Corsair XMS2 800mhz
520W Power supply

To the problem :

I cannot overclock my system more than 300 FSB, it worked fine with my old memory sticks (XMS2 667 mhz)

But everytime i try to overclock more than 300FSB I stop getting any response from the screen. It just stays black.

I have tried to mix with the Vcore and Vdimm and i am now running 300FSB with 2,1 Vdimm and 1,385 in Vcore. I cannot run the Vdimm under 2,1 because if i do, I'l gett the same problem i have when i override 300FSB

I have also tried to lower the divider to 667 mhz but my problem remains
Also, i have tried to set the North bridge to 1,4

Please excuse me for my bad english. I am a swedish 16 year old haha. But i realy hope you can help me

2.1v is really no prob for that RAM. 2.2 is also in the safe zone, 2.3 is pushing it a bit.

Try raising the NB voltage a bit, as well as FSB voltage.

I have tried to mix a but with the NB and SB but nothing helped =/

Try diff dividers if you can such as 400 fsb with 1:1 = 800mhz.

Do you have the command rate set to 1N or 2N?

And what revision? http://ramlist.ath.cx/ddr2/

I have tried different dividers also =/ nothing seems to work... How come my 667 MHz sticks can run it with no problem but with my 800 MHz i just cant reach over 300 fsb ? =S