When running a full screen video stream from YouTube, Hulu or NetFlix, the video may become choppy or the audio and video lose sync, even though the GPU may be at low utilization.
This is caused by a bandwidth limitation in the PCI-E 1X channel. While most desktop systems use a PCI-E X4 or X16 channel for the GPU, some laptops and systems with ION GPU's use a 1X channel. While this is typically sufficient for most videos, some streaming video content has multiple composited overlays for menu's, advertising and so on. This causes multiple trips through the bus, exceeding the available PCI-E 1X bandwidth.