Hmmm, getting some problems with my new pc and the 8GB RAM

First i'll tried to install Vista x64 (included SP1) and the Setup shows up that the kernel is corrupt...
Google told me to install with 4 GB RAM - That finished the Setup without any Errors

But now i want to use the 8 GB RAM

Wenn I try to install the 4th slot, Vista crashes on bootup with "IRQL_NOT_LESS_OR_EQUAL"
With 6 GB instead it works fine

To resolve the problem I have tried out:
- Fixing with the Microsuff Patch for more than 3GB - Doesn't work for me, says: "System doesn't match" - I'll think the patch is included in SP1
- Apply the correct value for the RAM in the Bios
- Bios Update to last revision

Now I'm at the end of my ideas...
I NEED UR HELP



Sry, for my bad english