Researchers at Microsoft and Duke University have developed a way to dramatically reduce the amount of bandwidth consumed by games streamed from remote servers. Dubbed Kahawai, the approach uses "collaborative rendering" to split the workload between the GPU on the server and the one on the client device. This virtual tag team consumes one-sixth the bandwidth of traditional streaming, the researchers claim, and there's supposed to be no impact on latency or image quality.
Kahawai actually comprises two separate techniques. One tasks the client GPU with rendering a subset of the frames required by the scene, while the server GPU fills in the rest. The other approach uses the client GPU to render each frame at a lower detail. Those frames are then combined with "a stream of per-frame differences to transform each frame into a high detail version." The specifics of how everything comes together are detailed in this paper (PDF).
And there's a video, of course. The clip below shows how Doom 3 looks when streaming at 1Mbps with traditional and Kahawai-based methods.
The 50 gamers who tested the system reportedly posted similar scores and response times to traditional streaming. Kahawai may not reduce the latency between the client and server, but at least it cuts bandwidth utilization without making things noticeably worse. That should make the tech appealing for slower-paced titles that aren't as sensitive to the input latency that affects all games streamed from remote servers. If only there were something researchers could do about that.