When it says 1GB DDR3, it means that the VRAM is DDR3 memory. VRAM does not interact with your motherboard in anyway, and is available solely for the GPU. For example, it is common to have DDR3 memory, with a video card that uses GDDR5. These two types of memory are separate from each other and do not interfere. A video card is itself a "tiny PC" if you will, with a processor, board, and memory. As long as the PCIe slot fits your motherboard and your power supply is able to accomodate the card, then you're all fine.