I have a stable system, just seeing if anyone has tried it yet or has some tips. I should receive the card today or tomorrow, I think I'll try the 1st slot AMD and 2nd or third Nvidia and see how it goes.
I'd say over 90% in this thread are using Skylake systems , so X99 is not that common, so the 2nd helper hgraphics card is not a common solution.
ekwipt,
I currently have an RX 480 running on a GA-X99-UD4 board with full acceleration. It's in slot 1 and there is an AMD Radeon 7950 in slot 2. Since I have a 5820K CPU, this allocates 16 lanes to slot 1 and 8 lanes to slot 2. The BIOS Initial Display Output is set to PCIe 2 slot. The 7950 is connected to my monitor via HDMI and the 480 is connected via DVI-D (I can’t get DP to work with this monitor - Philips Brilliance 288P).
I have made zero changes to my config.plist.
I patched the AMDRadeon4100.kext as follows:
Open info.plist in TextWrangler:
IOPCIMatch add: 0x67DF1002
Open AMDRadeon4100 in iHex:
Change number of CU's from 16 to 36:
48 B8 02 00 00 00 01 00 00 00 48 89 43 54 C7 43 7C 08 00 00 00
48 B8 04 00 00 00 01 00 00 00 48 89 43 54 C7 43 7C 12 00 00 00
Remove CU limit (didn't alter for P10):
0F 42 C8 89 8B 80 00 00 00 44 88 B3 99 00 00 00 44 88 73 20
90 90 90 89 8B 80 00 00 00 44 88 B3 99 00 00 00 44 88 73 20
Change init function to Ellesmere instead of Baffin:
E8 49 85 FE FF BE 48 01 00 00 4C 89 F7
E8 46 E4 00 00 BE 48 01 00 00 4C 89 F7
I patched the AMD9500Controller.kext as follows:
Open AMD9500Controller in iHex:
“Find” the text “xxx” and replace the "R9 XXX" with RX 480. Also replace the " ATY,Part#" text right after with "0" until the " ATY,Part#" is gone from the right hand side of the text view.
[Note: Those changes came from postings in other threads here, thanks to all that have worked on them!]
This configuration results in Metal support and full acceleration for both cards. The only slightly annoying thing is I have to change the monitor input source from HDMI to DVI after every boot, which takes about 2 seconds via the controls on the front of the monitor.
My latest LuxMark v3.1 score under 10.12.3 it attached.
Hope this helps.