Need help! :o

I have an PowerMac G5 2.0Ghz Dual Prosessor with DDR2 SDRAM and a GeForce 6600LE Graphics Card ..... But when i look for my model on the internet it says my model has DDR SDRAM not DDR2 SDRAM... Why? I have checked the info on the mac and it is DDR2 SDRAM... And another thing i have checked with a model id identifyer and it says i have a PowerMac G5 with DDR SDRAM not DDR2 SDRAM... And when i turn on the PowerMac and look at ''about this machine'' it says i have 2 processors and DDR2 SDRAM :/ My specs looks morel ike a Dual Core 2.0Ghz than a Dual Processor 2.0Ghz.....