I have an AMD driver issue too. I am running the same computer you are and my display driver crashes every time I play Star Trek Online. I wish i had not gone with windows 10.
I have the same issue,
I am running AMD Radeon M370x in a 2015 MacBook pro with windows 10 boot camp. I really want to be able to have the latest drivers that support newly released games i.e 16.x....... not 15.x.....
Additionally, since the new apple boot camp update as of the 04/05/16 my function keys (F1 and F2) no longer adjust the brightness.
For example, I want to play Total war Warhammer on Directx12 as of the latest game update, if I try to the game crashes, when the graphics card R9 series supports directx 12 on windows.
Surely this is for Apple and AMD to resolve as there is a growing amount of people wanting to play games on boot camp. see here.
It's always been my advice to anyone for whom gaming is more than just a casual, take-it-or-leave-it proposition, that they be kind to themselves and *not* buy a Mac...;) You are going to find no shortage of Windows applications available, and when it comes to gaming, Windows is the place to be--that's why Bootcamp exists, among other reasons. A Mac is fine if gaming is not something you like to do more than a little, imo. But the Windows selection of games, not to mention 3rd-party Windows hardware choices available for gaming (the drivers are all easily available from the peripheral manufacturer's web sites), absolutely dwarfs what is available for the Mac--there is no comparison. Maybe food for thought for your next purchase...
I gather you mean "a Mac with an AMD GPU in it" because Apple doesn't make an "AMD-based Mac", all Macs are Intel-based. You can't buy a Mac with an AMD CPU in it because Apple does not sell a Mac equipped with an AMD CPU, although it would run OS X (just MacOS now, I believe) as easily as the Intel cpu runs it. Anyway...
I'm not sure of the reason why you cannot use standard AMD Windows x86-64 drivers in Bootcamp running Windows 10 (because the Windows10 you install is the same one that anyone installs with or without a Mac), but I do know that in the Release Notes of every driver AMD puts up for download on its public web site, you'll find the following disclaimer in the first two lines:
This driver is not intended for use on AMD products running in Apple Boot Camp platforms. Users of these platforms should contact their manufacturer for driver support.
Now, what that says to me is that Apple has requested slightly customized AMD GPUs to go into its Macs, and therefore Apple, not AMD, is responsible for supplying you with your AMD GPU drivers. It's Apple you want to talk to about these issues--not AMD. This is exactly the same situation that many laptop owners face--often they use custom GPUs (different in some way from the retail AMD GPUs sold on store shelves) , and so the retail website drivers will not work--or work properly with them, and they must obtain their GPU drivers from the OEM who made their laptop. Caveat Emptor.
Having said that...have you tried to download and install a GPU driver from the AMD site? If not, you might want to give it it try just to see what happens. If it doesn't work the worst that will happen is that you'll have to reinstall the drivers Apple provides you for your GPU, even though they may be very old. Because of the agreement AMD has with Apple concerning its GPUs, I gather that the website drivers won't work--but you'll never know for sure unless you try.
I have often wondered, for instance, that if you bought a Mac with an open PCIe x16 expansion slot, why you couldn't just buy an AMD GPU from some retail outlet somewhere (Amazon/Newegg) , plug it in, and with Win10 and the AMD website Windows 10 drivers, go to town...! I can't think of why that would not work, but I don't know that it would--but again I should think it would work fine. You might want to try that if your Mac has a suitable expansion slot--which some Macs just don't have. Also you might need to know the wattage/Amperage support of the PSU Apple has put into your Mac, depending on the GPU you decided to install in your Mac. But then you'd have to concern yourself with MacOS drivers for your GPU....Ah, Apple complicates things so needlessly in the guise of "making it simpler"--when you want to expand, the Mac makes things a lot tougher, imo...;)
Anyway, I hope this will give you a bit of insight, maybe, into why things are as they are with Apple products. Additionally, things are exactly the same with nVidia GPUs should you have bought a Mac with a nVidia GPU on board--you have to get your Windows 10 drivers from Apple...and that's because of Apple, not AMD or nVidia...
Hey, I have the same Proplem, Macbookpro Mid15 / 64 bit / Win10 with bootcamp, as my previous speakers can not upgrade to new versions of amd. It would be great times when a statement of amd comes, then we must not think how such things between apple and win effect! Because honestly, I do not care who has where as how to blame, in fact I have an amdgrafik and that is not updatefähig. There are thousands of macbook sold, in all are now amdhardware! Because I need no longer think about who is my contact. Because apple says it s. amd and amd pushes it on apple, then I leave it halt and sell my hardware not to apple! There is probably a way to install the current versions manually, these run then synonymous to win10, since synonymous the win10 runs separately. Maybe someone is so nice and can record the way ?! A thousand thanks to you!