Gigabyte DS4+GSkill PC6400 Dual channel=UNSTABLE@Stock

[acode]

The system:

Motherboard:
Model Name : GA-965P-DS4
M/B Rev : C1
BIOS Ver : F4/F3/F5..

Graphics card: VGA Brand : BFG Model : 7900GT OC
CPU Brand : Intel Model : Intel core 2 E6600 Speed : 2.4Ghz
Operation System : Win XP 64-bit SP : 1

Memory:
Memory Brand : GSKILL Type : DDRII
Memory Size : 2x1GB Speed : 800mhz (PC6400)
Model number: F2-6400PHU2-2GBZX

PSU:
Power Supply : 450 W

The problem:

I cant get my system to run stable when my ram is set to 800mhz OR dual channel. Their stock settings are 4-4-4-12 v2.0-2.1 I raised the vdimm in the bios to +0.475. When the ram timings are on auto then I can get into windows but they fail stress tests ie. prime95. When i set them to 4-4-4-12 then they cant even boot up(the computer starts to reboot in a loop without posting).

On 533mhz it seams to be working fine..I tested different ram sockets and different ram blocks(with one of the ram being out and the other in and then swapped place in the next test..)

What am I doing wrong when Im trying to get a stable system using the ds4 motherboard? Ive tried numerous bioses..without any luck at all

Update: I also tried the F5B Bios, and that had no effect at all.

These are the settings I have in the bios in the tweaker menu:

MB Intelligent Tweaker
--Robust Graphics Booster: Auto
--CPU Host Clock Control: Disabled
--CPU Host frequency: 100
--Pci Express Mhz: 100
C.I.A: Disabled
System Memory Multiplier: Auto(I have also tried with manual and same problem)
Memory Frequency: 800
DRAM timing selectable: Manual
CAS Latency: 4
DRAM RAS TO CAS: 4
DRAM RAS Precharge: 4
tRAS: 12
(All those timings are according to stock)
Act to Act Delay: Auto
RANK Write to read delay: Auto
Write to Precharge Delay: Auto
Refresh to Act delay: 0
Read to Precharge delay: Auto
Memory Performance enhancer: Normal
DDR2 Overvoltage Control: +0.450V
(My ram wants 2.0-2.1v however they seam the most stable on this setting)
PCI Express Overvoltage control: Normal
(G)Mch overvoltage control: Normal
Fsb overvoltage control: Normal
Cpu voltage control: Normal
Normal CPU Vcore: 1.32500V

UPDATE!

I just tried with the newest Beta bios F5c and now one of the memory sticks work stable it seams on 800 mhz with all timings set on auto(which arent 4-4-4-12 like they should be). Everything else fails on arithmics(tested with SuperPI/Prime95).

I can see when I look through the other DS3/DS4/DQ6 threads that my vdimm voltage is quite high but if its higher then the system wont start(memory error) and if its lower then it goes into the infinate reboot state.

Im out of my witts here...What am I missing? Am I looking at defective Memory / Motherboard??