Memory speed changes depending on slots filled?

[marblewave]

Hi there,

I recently added a 1Gb stick of Ram to my existing 2x512 sticks and immediately began getting sync issues with my Firewire audio interface. I thought that perhaps I had an issue with the system being brought out of dual channel mode with the addition of the new 1Gb stick.

So, I replaced the 1Gb with another matched pair of 512 sticks to regain dual channel. It seems to have worked, except that when I have 2 banks filled I get dual channel at 400Mhz, but when all 4 banks are filled I get dual channel at 333Mhz, along with less frequent but still annoying sync issues.

Does motherboard architecture always reduce the overall ram clock when all 4 banks are full or is this a bios setting or something else I could be missing?

Thanks for your time!

P.S. all 4 sticks are PC3200...

 

[InlineFive]

Some older Dual-Channel motherboards pull back the speeds because they can't run all of the slots at the full speed. What chipset does your motherboard have?