No. SDRAM and DDR SDRAM are not compatible with each other.

The term DDR SDRAM refers to the phrase "double data rate synchronous dynamic random access memory". DDR SDRAM is simply a faster version of SDRAM in which data travels at a double rate. If your computer specs say that it uses DDR SDRAM it can take DDR SDRAM, but not SDRAM. DDR is 184 pins and has a notch in the bottom near the center and you will be unable to put DDR in an SDRAM mother board and also unable to put SDRAM in a DDR motherboard. Recently a new type of RAM has been introduced to market called DDR2. DDR2 is its own type and will not fit into a DDR motherboard. Hope this helps. Peace.

DDR SDRAM uses 184 pins.

No.

In order to upgrade SDRAM with DDR, you will need to replace your motherboard. DDR uses a different slot than SDRAM, so if your motherboard is using SDRAM currently, you will most likely have to replace your motherboard in order to make your system support DDR.