Asus P5W DH Deluxe & Corsair TWIN2X2048-6400 problems

[Luniz05]

Hello, my pc is :

Asus P5W DH Deluxe
Intel E6400 + stock cooler
Corsair TWIN2X2048-6400 CAS5
Leadtek 7900GT
Deluxe 500W power supply with 2 coolers.

Well i don't know why but my DDR2-800 are working on DDR2-664 (PC5300). I've modified it from bios, and it runs PC6400 but its unstable, it restarts over and over again.
I'll pushed the 1,9v to 2,1v... the timings 5-5-5-12-5 to 5-5-5-15-5 .. useless it restarts again. My PC it's running on stock speeds. Please help me!
I want to overclock my E6400 to 2,88 - 2.9 if i can with stock cooler, but if i know this should overclock my DDR2 too. What should i do ? How far can i push the E6400 with stock cooler ? what about my Rams ... i don't know what is the best for my pc...what should be the solution for it. Please help me!

 

[Kenyada]

You may want to determine whether your "Deluxe 500W" power supply will be up to the task. Your entire system will only be as good as its weakest link, and right now I see your PSU as suspect in an otherwise solid rig.

Read some reviews on power supplies - stability, reliability - particularly since you are interested in pushing your system as far as possible.