I am having a RAM problem.

[Firsttime]

I have had a DFI lanparty motherboard with 512MB of Kingston HyperX PC3500 running for awhile now. I had it overclocked to PC4000 speeds and whatnot. Now I just got another stick of HyperX 3500 to bring my total up to 1gig. However when I enter CPU-Z it tells me the new stick is 3200 even when its the only stick in. I bought the second stick brand new sealed and everything. I called my local store where I got it and they weren't sure what was wrong, they said my motherboard isn't even supposed to support 3500, but CPU-Z has been reading my older stick as that for awhile. Any help would be much appreciated.