NOTE: This method does not currently work with macOS Sierra 10.12, please use method 2 below and run the AGDPFix v1.3 utility.
1.Open your Clover config.plist using text edit and scroll till you see <key>KernelAndKextPatches</key>
2.In that section you will want to add the following:
<key>KextsToPatch</key>
<array>
<dict>
<key>Comment</key>
<string>(c)Pike R. Alpha</string>
<key>Find</key>
<data>
Ym9hcmQtaWQ=
</data>
<key>Name</key>
<string>AppleGraphicsDevicePolicy</string>
<key>Replace</key>
<data>
Ym9hcmQtaXg=
</data>
</dict>
3.
4.Save your config and now your kext will be patched when you boot by changing board-id to board-ix.
Method 2:
Use Shilohh's AGDPfix found here: http://www.tonymacx86.com/threads/b...-imac-15-or-imac-17-system-definition.183113/
Method 3:
1.Open Terminal
2.Enter this command (it is one line)
sudo nano /System/Library/Extensions/AppleGraphicsControl.kext/Contents/PlugIns/AppleGraphicsDevicePolicy.kext/Contents/Info.plist
3.
4.Arrow down to where you see <key>ConfigMap</key>
5.For the iMac15,1 locate the board-id "Mac-42FD25EABCABB274" and change string below it from "Config2" to "none". For the MacPro6,1 you will do the same thing but for the board-id "Mac-F60DEB81FF30ACF6". For the iMac17,1 you'll have to see which board-id is declared in your config.plist SMBIOS: "Mac-B809C3757DA9BB8D" or "Mac-65CE76090165799A" or "Mac-DB15BD556843C820" and change the appropriate entry to "none".
6.Save the file by pressing Ctrl+O, then enter.
7.Exit by pressing Ctrl+X
8.Rebuild the kernel cache using the following two commands in terminal:
NOTE: you may need to use kext-dev-mode=1 if not already using it to allow the modified kext. For El Capitan you will need to at least partially disable SIP to allow the now unsigned kext.