I install windows 8.1 on my iMac 5k with amd r9 295x and installed the drivers from boot camp but when I go to control panel to amd to update the drivers, the procedure complete fast no errors but the drivers remain the same. I try to uninstall them and to download from the site of amd but again the procedure finish and the drivers remain the same. Very frastaited cause I can't update the drivers. The iMac seems slow on the windows and I believe of the drivers. Any help?