Vista - BSOD Stop 0x0000001E

Hi all,

it seems my new built computer has problems when it is "cold". I often get a Bluescreen the first one or two times when booting up.
Strangely enough after the one or two times booting, it is totally stable after that.

They are always similar:
Stop 0x0000001e

only BCP1 varies

BCC 1e
BCP1 varies between

FFFFFFFF80001A57800,FFFFFFFF80001E98800,FFFFF80001E64800,
FFFFF80001C58800
etc.

BCP2 0x0000000000000000
BCP3
BCP4 0x000000000000003E

Though i set it to generate minidumps I can't find any after Bluescreens.

I installed Windbg and both symbolpacks for Vista SP1.

I alread switched the 2GB modules against 2 other 2GB modules and still Bluescreens.
So what would you suspect ? CPU bad, mainboard bad or PSU?

Could a be a hotspot because the thermal grease is not evenly pasted?

I really ran out of clues what to do next. Alread reinstalled and updated BIOS, drivers etc.