[SUCCESS] Gigabyte Designare Z390 (Thunderbolt 3) + i7-9700K + AMD RX 580

[CODYQX4]

Thank you for the detailed writeup. The main takeaways are:

• New BIOS does not help (yet) with Thunderbolt monitors (particularly when using iGPU to drive Thunderbolt display)
  • There is no video signal during POST and OpenCore Picker
  • It is necessary to connect a regular monitor and then connect the TB monitor after macOS has loaded, then unplug the regular monitor
• One difference noticed with new BIOS:
  • In BIOS Setup, when both regular and TB monitors are connected, then TB monitor will display BIOS or POST screen for a second, then both monitors lose video signal

I wonder if we need to import an Apple video DXE/PEI driver as well...

In almost all cases, the TB monitor almost never shows anything, or even lights up. I don't know if what I did works on the old BIOS, but the most consistent way for me to cause it to happen was to enter BIOS setup with a standard monitor (I'm using an LG 27UK650 over HDMI) then plugging the Thunderbolt cable into the LG UltraFine 5K (already plugged into AC power), waiting for video loss, then holding down the case power button and quickly pressing it to power back on.

The video import sounds interesting, as I suspect the BIOS fails to initialize the monitor on it's own without dGPU. I've also been curious how it handles in an RX 6800 XT USB-C port, but I haven't been able to get one.

 

[Inqnuam]

@Elias64Fr,

Here's a table of similarities and differences. I'll keep this table updated as more information comes in. Hopefully it may help us identify the culprit.

Owner / System	CPU	BIOS	IOReg	Issues
@Elias64Fr Designare Z390	i5-9600K iMac19,1	Modified v003	AppleVTD DMAC	None
@Inqnuam Designare Z390	i9-9900KF iMacPro1,1	Modified v003	AppleVTD DMAC ??	None
@CaseySJ Designare Z390	i5-9600K iMac19,1	Modified v003	AppleVTD w/ and wo/DMAC	None
@yosoyoco Designare Z390	i9-9900K iMac19,1	Modified v003	AppleVTD DMAC ??	Ethernet/WiFi No Connect
@NCMacGuy Designare Z390	i9-9900K iMac19,1	Modified v003	AppleVTD w/ and wo/DMAC	Ethernet/WiFi No Connect
@CODYQX4 Designare Z390	i9-9900K iMac19,1	Modified v003	AppleVTD w/ and wo/DMAC	Ethernet/WiFi No Connect

No DMAC for Inqnuam!

Note that I'm the only one with iMacPro1,1 on i9-9900K* in the list of testers

 

[CaseySJ]

Interim Update #2B:

I have two Z390 Designare systems:

1. Test Bench with i5-9600K
   • No Ethernet/WiFi problems with VT-d enabled
   • Big Sur 11.5 Beta 3
   • Two DIMM modules (16GB total; XMP Profile 1; 3200MHz)
   • Fenvi FV-T919 in PCIe x1 slot
   • AMD R9 380 --> 1440p Monitor
   • iMac19,1
2. Primary with i7-9700K
   • Just installed new BIOS and enabled VT-d
   • This system has Ethernet and WiFi connection problem
     • UPDATE: Works perfectly with 2 DIMMs! See below.
   • Big Sur 11.5 Beta 3
   • Four DIMM modules (32GB total; XMP Profile 1; 3200MHz)
   • Fenvi FV-T919 in PCIe x1 slot
   • AMD RX 5700XT --> 4K Monitor
   • iMac19,1

 

[CaseySJ]

No DMAC for Inqnuam!
View attachment 522724
Note that I'm the only one with iMacPro1,1 on i9-9900K* in the list of testers

Three questions:

• How many DIMMs?
• Total memory?
• Memory speed?

 

[CaseySJ]

** AppleVTD Ethernet/WiFi PROBLEM IDENTIFIED **
​

@Elias64Fr @Inqnuam @yosoyoco @NCMacGuy @CODYQX4 @gandem @qthegaijin,

If the motherboard has only two DIMMs (in slots A1/B1 or A2/B2) then Ethernet and WiFi are fully functional with VT-d enabled! I just removed two of the four DIMMs from my Primary Z390 Designare and now it's working fine.

NOTE: Requires 8GB DIMMs. Higher capacity DIMMs may need “PlatformInfo —> Memory” to be filled out.

 

[trs96]

I just removed two of the four DIMMs from my Primary Z390 Designare and now it's working fine.

Can you explain why ? What about people that need to use four 16 GB DIMMS ?

 

[yosoyoco]

** AppleVTD Ethernet/WiFi PROBLEM SOLVED **​

@Elias64Fr @Inqnuam @yosoyoco @NCMacGuy @CODYQX4 @gandem @qthegaijin,

If the motherboard has only two DIMMs (in slots A1/B1 or A2/B2) then Ethernet and WiFi are fully functional with VT-d enabled! I just removed two of the four DIMMs from my Primary Z390 Designare and now it's working fine.

View attachment 522731View attachment 522732

Congratulations ! I have four dimms, I hope we can find a solution to keep my 64GB

 

[CaseySJ]

Can you explain why ?

I simply looked for differences between my two systems. Realizing that the working unit has 2 DIMMs and the non-working unit has 4 DIMMs, process of elimination demanded that I remove two of the four DIMMs from the non-working system. And voilà.

What about people that need to use four 16 GB DIMMS ?

I didn't say it was a perfect solution!

Now that we know what causes the problem, the next step is to see if there's a proper solution...

 

[CaseySJ]

Congratulations ! I have four dimms, I hope we can find a solution to keep my 64GB

Up to now the Antelope Interface had 0% connection success. Now it has 100% success, but the penalty is half the number of DIMMs. Tradeoffs. But let's see if a proper solution can be found.

For example, if we enumerate the 4 DIMMs in PlatformInfo --> Memory, will it help? Will try soon.

 

[yosoyoco]

Up to now the Antelope Interface had 0% connection success. Now it has 100% success, but the penalty is half the number of DIMMs. Tradeoffs. But let's see if a proper solution can be found.

For example, if we enumerate the 4 DIMMs in PlatformInfo --> Memory, will it help? Will try soon.
View attachment 522738

You’re a genius !