Sorry, but this is not true at all for like years.. They have their Catalyst mobile drivers which should be possible to install on any supported cards. The manufacturers only provide certified drivers in some cases (like for professional laptops). E.g. some time back I've installed M7820 FirePro card (basically a pro edition of the 5870M) into my old backup Dell Precision M6400 workstation, downloaded Catalyst GAMING (not FirePro) drivers and installed them with no fuss. Nvidia allows the same thing for their Quadro series (I've used FX3700M on that laptop before switching to the AMD as it consumes less and is somewhat newer tech).