Any additional idea to solve my coldbug-problem?

CPU: Opteron 144

MoBo: DFI NF4 Ultra-D

RAM: OCZ VX

I set up my first DICE-cooling and run as a lot of other people in a coldbug-problem...

If I start without cooling and then bring temperatures down for example @ 305 x 9 OS freezed at about 15°C.

I tried right now followings BIOS-files: 702-2, 702-1, B14 (latest from DFI) and 406BTA

Works perfect at BIOS, but freezes with the Opteron in Windows with HTT > 200 MHz.

The 3200+ Winchester from my girlfriend worked fine (scrappy CPU, doens´t do 2,4 GHz @ AutoVcore at my DFI)...