80 Column Mind
Let's see, A) Windows 8 has not shipped to the end users, only to OEMs and MSDN subscribers, and B) OEMs support their own laptops, AMD only provides a generic driver. Oh, and not to mention AMD DOES NOT SUPPORT LAPTOPS WITH SWITCHABLE GRAPHICS, as it is stated clearly in the driver notes. So the answer is "whenever Lenovo decides to put one out."
AMD FX-8350 w/ Corsair H105, ASUS Sabertooth 990FX Gen3/R2, 8GiB G.SKILL DDR3-2133, XFX HD 7970 GHz Edition, 1TB Samsung 850 Evo, 256GB OCZ Vector, Creative X-Fi Titanium w/ Creative Gigaworks S750, SeaSonic X750, Corsair C70, HP ZR2440w, Win 7 Ult Ed x64