Architectural advantages of integrated GPUs?

Is there any sense in which integrated GPUs outperform dedicated GPUs when matched spec for spec? In other words, does the GPU being embedded on the same chip as the CPU provide any advantages in terms of bandwidth/latency that means they can outperform matched GPUs which have to communicate via PCIe? What about in the future?10.0.0.0.1 192.168.1.254 happymod