Graphics card Mem Speed & Mobo Mem Speed

[Alex Pantelides]

Hello, i want to upgrade my graphics card but i don't know if the new card will underperform if the card's memory speed is more than the motherboard's memory speed. I am using a gigabyte GA8S661FM which works at a max of DDR400, but the card i am thinking of buying, the Nvidia 6800Ultra works at 800Mhz. Does that mean that the card will be affected and downperform?

Thank you for your help everyone.