Help! memory problem!

[Yngvi]

I recently build an i7 system
i7 920
Asus Rampage II Gene
Corsair XMS3 1600mhz C9
etc. thats the important stuff.

Now i smacked it together, as it was my first build i was very happy that it turned on when i pushed the button, something i did right yae!

I installed win7 home premium 64 bit, and everything worked like a charm. Except this one thing.
4 gb of ram!
Now i turned off the rig, went to the bios and switched the frequency back to 1066mhz, and now all 6 were found.

However at 1066 the morning after it would not find anymore than 4gb again, so i switched the dream freq to 1333, and now all 6 were found. Same problem next day, and now im switching from 1600 to 1333 everytime i boot up, meaning i can find all RAM, if i just switch my dram frequency, not that 1600 is too much, as long as i change the value it will find it all.

Im really confused, if this is my mobo ram or cpu, as the i7's have the mem controller on the dye.
When i memtest all 3 (havent tried 1 1 and 1) there are no errors at all, works just fine, and i dont have any other complaints about my rig.

I have seen others only finding 4 gig's, but none fixing it by just changing the Dram.

Any advice? Any components sound dead?
I have not overclocked anything, except switching from 1066 standard to 1600 wich my RAM is rated for

DRAM Bus 1.65v
QPI/Dram Core 1.35
Dram freq 1333/1600 (switching every day)
9-9-9-24
Just as my RAM is supposed to be running!

CPU settings are auto everything.

 

[Lutfij]

the frequency flux could indicate some problems from ur mobo. either its being frisky with the bios, did u try updating the bios version on ur board? try taking the battery out and insert it again. See if this helps without loading into bios and changing frequencies.

if it persists then an RMA may b around the corner... btw wats ur PSU?

 

[Yngvi]

Cooler Master M 700w
And im running the latest Bios version
EDIT:
I dont know if its the same as popping out the battery, but i have cleared the CMOS before, with same stuff happening again.

Now the people i bought my CPU from are kind enough to RMA my CPU without any hazzle, so im going to do that just to make sure the memory controller isnt causing this.

 

[Lutfij]

ur power supply checks out fine...let us know wat happens after the return

 

[Yngvi]

If however changing the CPU does not fix anything i could try checking if my RAM works in my friends i7 build.

If thats the case, and my RAM works, then im guessing the mobo is faulty (w00t hard to figure out!)

The place i bought my mobo and ram is not the same store as the CPU, and they dont have great service over there, they charge 400 DKK just for error checking 1 hour. Thats about 80$, its free if there is something wrong with the product though. I just want to make sure that i have done anything i can at home before i send it back.

 

[Lutfij]

do ur hardware check with ur friends build...card, ram and see if they bootup without a problem and check bios to confirm no errors. Then use ur board with ur friends hardware - cross referencing it will narrow the problem down - if it really is ur board