Ok, I've made some more tests... and i was some kind of successfull!
RX460 card is plugged into PCI-Slot#1... no Monitor attached to it. Internal INTEL HD530 switched on via BIOS (Settings: primary GFX is Onboard, Shared Memory is set to 64MB, Multimonitor is enabled). Connect Monitor to either HDMI, DP or DVI and boot to System.
Following Settings in CLOVER config.plist:
Inject ATI: true
FakeID: 0x0
VideoPorts: 7
Inject Intel: true
ig-platform-id: 0x19120000
With this config i booted into SIERRA DeveloperBeta 6 (built 16A294a). Opened Systemmonitor to check, if AMDRadeon4000.kext was loaded:
Guess what: as you can see -
it truely was loaded!!! So i switched Monitorcable (used DP here) from INTEL onbaord into RX460 DP-Port. Et voila: i got full resolution and
FULL accelleration. YEAH.
Now i just got one problem: even if Primary Grafikadopter is set to "Onboard", system allways started from RX460 as primary card when Monitor is connecte to both internal HD530 and RX460, which results in NO GO. It only works when HD530 is really the primary or only GFX-card detected on PowerOn System or Reset System.
I was not able yet to get my system work with Monitors connected to both cards and make the HD530 the real primary GFXcard. It allways use the RX460 to diplay BIOS settings, whenever it detects a connected monitor. Hope you understand what i mean with that - don't know how to describe it better in english (not my native language).
So if there is anyone around there to tell me how to get this problem fixed, i am half way done in using the Sapphire RX460 NITRO.
Oh, one thing i forgot to mention: with all the above discribed, i no longer have to change device-id of RX460 from original 67ef1002 to 67df1002 - i just let the system detect the correct device-id.
I will test it with RX480 later this day and keep you informed.