Problem between Dominator Twin2X2048-8888C4DF and Asus P5B Deluxe mobo

[ColdFire]

For around a year, I've used without problem 2GB of Dominator Twin2X2048-8888C4DF on an Asus P5B Deluxe motherboard, with a Core2Duo E6600. The ram was set as PC8500 in the bios.

But since a few days, I can boot my PC only if I have ONE module inserted, always the same one (call it module 1, the faulty one is module 2).

Here are the tests I've done:

 

Module 1 and 2 inserted, whichever the slots of the mobo: PC doesn't boot (no display, fans run, HDD are started, no BIOS bip)

 

Module 1 in whichever slot, module 2 not used: PC boots fine

 

Module 2 in whichever slot, module 1 not user: PC doesn't boot

 

Module 1 in bank 1 and a PC5300 1GB HP module in any other bank: PC boots fine

 

The ram is set in BIOS to automatic (so with the HP ram, it starts as PC5300, without it, as PC6400), including memory voltage.

The RAM voltage has always been set in bios to automatic, I've never modified this setting.

I can't run memtest on the module 2 since the pc doesn't boot with it.

I still have to test module 2 in another PC (probably an HP one at my work).

 

Any idea? My PC hardware should be readable in my profile.

 

Thank you!

 

Edit: the BIOS is up to date

[RAM GUY]

The minimum suggested voltage for these modules would be 2.4 volts. Please set this in the BIOS and see if you are still having the same issues. These modules would not be stable at the default settings, and would not be compatible with OEM systems such as DELL or HP.

[ColdFire]

Even if I use the ram as PC6400?

 

CPU-Z says this about the ram:

 

270MHz 4-4-4-13-15 et 1.8V

400MHz (PC6400) 5-5-5-18-22 at 1.8V

555MHz (PC8888) 4-5-5-12-31 2T at 2.4v

 

I'll test today setting the DDR voltage to 2.4V, we'll see.

[RAM GUY]

The memory is tested at 2.4 volts to run at 1111MHz with timings of 4-4-4-12. Since they are not tested at any other settings, we can not guarantee that different settings would be stable, and the memory may not be stable at all at the default voltage.