I dont know the make of the video card

Hi,
I have a video card, but i cant tell the make of it. Someone replaced my working NVida card with this unknown one. I dont know which driver to get for it. It does not say on it. There are no markings. I think it is under the heat sink. But i cant remove the heat sink, it would get damaged.
Is there another way of determining what kind of video card i have.?
Thank you