According to the source, ACC won't be exclusive to AMD for long. If the slide below is true, NVIDIA's plans regarding MCP72/78 unambiguously indicate the complete support of AMD ACC. The company will just have to use the JTAG interface and introduce certain changes into topology, connecting CPU and MCP72/78. The first motherboards on MCP72/78 with ACC support are expected on September 1.
Note that not all MCP72/78-based motherboards can offer ACC support, since it requires hardware modifications.