RAM weirdness

[un om bun]

I have 2 x 256 DDRAM 2700
In BIOS I changed it's frequency from 133 to 166, but when I checked my system in windows, it said that I had only 256 RAM. If I undo this, then it recognizes all my 512 again. Plus I have there options like 200, Turbo and Ultra so I guess that at 166 it must work !
Weird thing is that a friend of mine did the operation and it came out just fine. But after he left and I restarted my computer (without even entering BIOS), I saw 256 again. So is this some kind of a joke ? What am I supposed to do ? Laugh ?
Please help a good man. :smoking:

 

[Asus]

They should run at 166mhz is all I can say.
What board are you running?
Can you set it to SPD and auto timings?

 

[un om bun]

When I leave it to auto... everything is fine. I should probably get an expert to look at the whole system and optimize it a little.