DDR and SDRam

I currently have a U8868 mother board. I have 2-SDR slots and 2-DDR slots. I have one SDR 512mb stick currently. These are clocked at PC2100 and PC133. I just bought a 1GB PC3200 DDR stick. When I install it, the reading still shows as a 512 mb, is this because of the clock speed and will I get the full 1GB?I took out the 512mb sdr.

Thanks for any help