3- Download & install lastest Chameleon or Clover from web.
4- Download lastest kext utility from web.
5-1- Extracted kexts copy and paste to /System/Library/Extensions and click change, okay (enter password) and open kext utility.app and enter password and click okay than see enjoy and click quit button and restart.
5-2- Or extracted kexts drag and drop to kext utility.app and enter password and click okay than see enjoy and click quit button and restart.
AMD R7 250 by KemalALKIN - Major Hint! - Please Read !
Full speed performance for plase change smbios.plist file:
Change mac type to MacPro5,1 because:
Edited speed lines in AppleGraphicsPowerManagment.kext ; MacPro5,1lines.
Delete This KEXT :
System --> Library -->> Extensions ;
Start with MacPro5,1 = kernel panic | solution = delete this AppleTyMCEDriver
And switching very very fast no freeze in tab switch for fast speed = delete this folder in System --> Library --> Extensions AppleUpstreamUserClient.kext
" This driver only all AMD R7 250 GPU Models "
Note 1 : Resolution & refresh rate change perfectly work and glass menubar = %100 working your AMD R7 250 graphic card.