I believe it uses requestAnimation frame. As the scirramark test queries for support for it when you run the test. I believe I also saw it somewhere I the documentation. The thing you need to watch out for in some isntances is that IE does not support webGL and IE is the underlying rendering engine for Native windows 8 apps. A good resource for Windows 8 specific questions as well is @thehen as he has already published to the Windows store and done work on optimization around it as well as written the Windows 8 Plugin.