This is what their website saying about their product:
CoreCodec CoreAVC® 2.0 for Windows is a complete solution for playing high quality HD H.264 videos on your Windows based computer. CoreAVC comes (in part) from the creators of the Matroska MKV Container (.mkv)
CoreAVC 2.0 fully supports GPU hardware acceleration with NVIDIA CUDA Technology, and works with other compatible NVIDIA Platforms like ION running on Windows XP, Vista, or 7.