SOLVED - Anyone has 5k iMac and suffers driver issues in windows 10 gotta see this
I got a 5k iMac with r9 m295x graphic card, since windows 10 released I have tried to have it on my iMac via bootcamp, however the drivers issues annoyed me a lot. There are two mainly problems when you install bootcamp drivers (get from Boot Camp Assistant in mac) in windows: keyboard function key and graphic card.
Here is the solution, after your windows 10 is installed
1, Get bootcamp drivers for windows as what you used to from boot camp assistant in mac.
2, Find the keyboard driver in your usb, location will be USB/BootCamp/Drivers/Apple/AppleKeyboardInstaller64.exe, and replace it with https://drive.google.com/file/d/0B3W9DOPdr9lsbnNkaHh2RVFoYXM/view?usp=sharing
3, Install BootCamp as usual in windows and reboot as it required.
4, Go to device manager and expand Display adapters, double click your AMD Radeon R9 M295X card, select the Driver tab and click Uninstall, make sure the checkbox has a checkmark for delete driver in the popup window and click Ok.
5, Wait for it finish, go to amd website and download latest windows beta driver for windows 8.1 64-bit, http://www2.ati.com/drivers/beta/amd-catalyst-15.6-beta-software-suite-win8.1-64 bit-june22.exe
6, Run the installer so it expands the files, then it will fail to install, now go back to device manager, double click your default video adapter (if cannot find it, click Action in the menu bar and then select Search for hardware changes), go to the Driver tab and click Update driver, choose Search my computer, then browse to the folder you just expand the beta driver and choose include subfolders.
7, Click OK, magic happens!! The driver will be installed and the adapter turns to be AMD Radeon R9 200 Series.
Now you can adjust the resolution and have full function of m295x!! Finally!!
iMac with Retina 5K display, Other OS, windows 10