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[Success] Radeon RX 6800 XT - Big Sur

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Are there any benefits in getting rid of WEG? Doesn't it help with other things, too?
Well using WEG on GPUs that have natively supported hardware encoding/decoding actually gets broken.
 
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I added a 6900XT and removed the Radeon VII and now my machine just freezes after barely any use (WEG is off). I tried changing PCIe slots for the Titan Ridge card, jumping pin 3 and 5, etc. Removing the Titan Ridge card is the only solution.

Any ideas appreciated.
 
Joined
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I added a 6900XT and removed the Radeon VII and now my machine just freezes after barely any use (WEG is off). I tried changing PCIe slots for the Titan Ridge card, jumping pin 3 and 5, etc. Removing the Titan Ridge card is the only solution.

Any ideas appreciated.
Shouldn’t there normally be a DP-pass through cable for the TB card that goes needs to go into the back of your motherboard’s DP socket? Have you attached it? Also make sure the TB card is on the last available PCIe slot in your system (that’s the standard default setup).
 
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Hi all,

Wondering if someone would have a suggestion. I posted this issue in one of the golden build threads that I keep an eye all the time but given that this forum is dedicated to graphics, I might be luckier. I have a Z490 Vision D and I was finally able to install the 6800XT that had been sitting in its box for the past 3 months following the release of 11.4.
But I have some issues during POST. I simply have no video signal during POST when using DP to DP cable. The system is booting and it is loading macos because once macos is loaded, I have a video signal and a full 4k@60Hz resolution. It is just during POST. It is annoying for several reasons amongst others:
- I can't get into the BIOS if I need to
- I can't get to OC picker to boot Windows if I need to or even when updating OpenCore
- I can't select another boot drive via F12 if needed

I did a few experiments based on suggestions from the golden build forum:
1. DP from the 6800XT to HDMI on the monitor via DP to HDMI cable: I have video signal during POST all the way to macos. But because I am using an HDMI input on the monitor, I can only get 4k@30Hz (not 60Hz) due to the monitor limitations.
2. HDMI from the 6800XT to HDMI on the monitor: same as above.
3. With a DP 1.2 cable and DP to DP, the video shows up when macos is loaded. With a DP 1.4 cable and still DP to DP, the video shows up a bit earlier (when the Apple logo and the progressing bar are displayed) but still misses the POST.
4. Following a suggestion on a separate forum, the 6800XT is now powered by 2 x 8 pins (6 pins + 2 extension) cables connected to my power supply as opposed to one cable with a splitter. When I rewired the power cables I also unplugged the monitor, waited about a minute and plugged it back. Upon starting up I missed the gigabyte logo (but that is understandable because my monitor is a bit old and slow to react) but I got the Oc picker. Unfortunately it worked only once. The next time I restarted the system either via "restart" or shutdown then restart, I had no video signal until macos loaded.
5. in the monitor settings, selected DP 1.1 instead of 1.2. The end result was similar to using the DP 1.4 cable; no video during POST then Apple logo/progressing bar and then macos. And limited to 4k@30Hz.
6. Updated the BIOS to the latest version. Same issues. No video during POST.
7. Relocated the 6800 XT in the second slot. Same result. No video during POST
8. Tried all the DP ports on the card with DP 1.2 or DP 1.4 cable; same issue.

Last suggestion that was given to me but I have not tried yet is the enable CSM in the BIOS.

Note that prior to the 6800XT I had a 5600XT and no issue during POST. I have exhausted all avenues I could read on the net. Only thing I can think of is a compatibility issue with the monitor which is a bit old (2015) when using that card and DP to DP cable.
I will also rule out an issue with the power supply. The power supply is only 2-3 months old and it is a 1000W.
I only get video during POST if I use an HDMI input on the monitor.

PS: recently read on another forum someone having black screens (but still able to POST) when running some rendering applications in windows and the solution was to increase the VCCSA and VCCIO to 1.3V in the BIOS. Not sure if it would help but worth mentioning.

Thanks for the help/suggestions.
 
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Shouldn’t there normally be a DP-pass through cable for the TB card that goes needs to go into the back of your motherboard’s DP socket? Have you attached it? Also make sure the TB card is on the last available PCIe slot in your system (that’s the standard default setup).

Is that really necessary though in this case? Previously I had a Radeon VII and this issue didn't happen.
 
Joined
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Gigabyte B550 Vision D
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RX 6800
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Hi all,

Wondering if someone would have a suggestion. I posted this issue in one of the golden build threads that I keep an eye all the time but given that this forum is dedicated to graphics, I might be luckier. I have a Z490 Vision D and I was finally able to install the 6800XT that had been sitting in its box for the past 3 months following the release of 11.4.
But I have some issues during POST. I simply have no video signal during POST when using DP to DP cable. The system is booting and it is loading macos because once macos is loaded, I have a video signal and a full 4k@60Hz resolution. It is just during POST. It is annoying for several reasons amongst others:
- I can't get into the BIOS if I need to
- I can't get to OC picker to boot Windows if I need to or even when updating OpenCore
- I can't select another boot drive via F12 if needed

I did a few experiments based on suggestions from the golden build forum:
1. DP from the 6800XT to HDMI on the monitor via DP to HDMI cable: I have video signal during POST all the way to macos. But because I am using an HDMI input on the monitor, I can only get 4k@30Hz (not 60Hz) due to the monitor limitations.
2. HDMI from the 6800XT to HDMI on the monitor: same as above.
3. With a DP 1.2 cable and DP to DP, the video shows up when macos is loaded. With a DP 1.4 cable and still DP to DP, the video shows up a bit earlier (when the Apple logo and the progressing bar are displayed) but still misses the POST.
4. Following a suggestion on a separate forum, the 6800XT is now powered by 2 x 8 pins (6 pins + 2 extension) cables connected to my power supply as opposed to one cable with a splitter. When I rewired the power cables I also unplugged the monitor, waited about a minute and plugged it back. Upon starting up I missed the gigabyte logo (but that is understandable because my monitor is a bit old and slow to react) but I got the Oc picker. Unfortunately it worked only once. The next time I restarted the system either via "restart" or shutdown then restart, I had no video signal until macos loaded.
5. in the monitor settings, selected DP 1.1 instead of 1.2. The end result was similar to using the DP 1.4 cable; no video during POST then Apple logo/progressing bar and then macos. And limited to 4k@30Hz.
6. Updated the BIOS to the latest version. Same issues. No video during POST.
7. Relocated the 6800 XT in the second slot. Same result. No video during POST
8. Tried all the DP ports on the card with DP 1.2 or DP 1.4 cable; same issue.

Last suggestion that was given to me but I have not tried yet is the enable CSM in the BIOS.

Note that prior to the 6800XT I had a 5600XT and no issue during POST. I have exhausted all avenues I could read on the net. Only thing I can think of is a compatibility issue with the monitor which is a bit old (2015) when using that card and DP to DP cable.
I will also rule out an issue with the power supply. The power supply is only 2-3 months old and it is a 1000W.
I only get video during POST if I use an HDMI input on the monitor.

PS: recently read on another forum someone having black screens (but still able to POST) when running some rendering applications in windows and the solution was to increase the VCCSA and VCCIO to 1.3V in the BIOS. Not sure if it would help but worth mentioning.

Thanks for the help/suggestions.
Hi emistral,

I may be able to help you. I had managed to recently run my RX6800 on my B550 Vision D system. This is what I'd done:

a) Enabled Above 4G Decoding
b) Set PCIe 16x slot to Auto, installed card on Slot 1
c) Used OC 0.6.9
d) Only SSDT-EC-Desktop.aml in ACPI
e) Enabled Lilu, Whatevergreen, AppleALC, VirtualSMC, USBPorts in Kernel
f) Used agdpmod=pikera as boot-args
g) Used iMacPro1,1 as SMBIOS
h) Set device properties as follows:

PciRoot(0,0)/Pci(0,3,0x1)/Pci(0x0,0x0)
Key: AAPL, slot-name
Value: Internal@0,3,1/0,0/0,0/0,0
Type: STRING

Key: device-id
Value:BF730000
Type: DATA

Key: device_type
Value: VGA compatible controller
Type: STRING

Key: framebuffer-fbmem
Value: 00009000
Type: DATA

Key: model
Value:Radeon RX 6800
Type: STRING

i) Booted from 2nd HDMI port on card to HDMI monitor, but had to wait for over 3 mins with totally blank screen before I saw macOS login. If this happens for more than 5 mins you may have to turn monitor off first then on again before macOS screen reappears.

As to CSM I wouldn't recommend enabling it in the BIOS though (doesn't help).
 
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Is that really necessary though in this case? Previously I had a Radeon VII and this issue didn't happen.
Yes I would think so, considering the RX6800/6900 is a different beast altogether to the Radeon VII. Considering it is utilising the full PCIe bandwidth it would have a totally different architecture. In any case it is worth testing out to see if that really is the issue.
 

CaseySJ

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I added a 6900XT and removed the Radeon VII and now my machine just freezes after barely any use (WEG is off). I tried changing PCIe slots for the Titan Ridge card, jumping pin 3 and 5, etc. Removing the Titan Ridge card is the only solution.

Any ideas appreciated.
If you recently updated to Big Sur 11.3 or 11.4, then it may be necessary to flash a different firmware on the GC-Titan Ridge if the firmware was previously flashed. Specifically, we should flash either the Z390 Aorus Xtreme or Z390 Designare or DSM2 firmware. All of these are available in the Thunderbolt repository.

However, if the original firmware is still installed, then we’ll need to explore other solutions.
 
Joined
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Messages
244
Motherboard
Gigabyte Z490 Vision D
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5600XT & 6800 XT
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Hi emistral,

I may be able to help you. I had managed to recently run my RX6800 on my B550 Vision D system. This is what I'd done:

a) Enabled Above 4G Decoding
b) Set PCIe 16x slot to Auto, installed card on Slot 1
c) Used OC 0.6.9
d) Only SSDT-EC-Desktop.aml in ACPI
e) Enabled Lilu, Whatevergreen, AppleALC, VirtualSMC, USBPorts in Kernel
f) Used agdpmod=pikera as boot-args
g) Used iMacPro1,1 as SMBIOS
h) Set device properties as follows:

PciRoot(0,0)/Pci(0,3,0x1)/Pci(0x0,0x0)
Key: AAPL, slot-name
Value: Internal@0,3,1/0,0/0,0/0,0
Type: STRING

Key: device-id
Value:BF730000
Type: DATA

Key: device_type
Value: VGA compatible controller
Type: STRING

Key: framebuffer-fbmem
Value: 00009000
Type: DATA

Key: model
Value:Radeon RX 6800
Type: STRING

i) Booted from 2nd HDMI port on card to HDMI monitor, but had to wait for over 3 mins with totally blank screen before I saw macOS login. If this happens for more than 5 mins you may have to turn monitor off first then on again before macOS screen reappears.

As to CSM I wouldn't recommend enabling it in the BIOS though (doesn't help).
Hi there,

Thanks for the help. Here are some comments:
a. Done. always been enabled. Part of the golden build guide.
b. don't have this option in my bios
c) already using it, even before installing the 6800XT
d) Can't have only this SSDT in ACPI. Need several SSDTs to fix wake/sleep, etc. As per above, part of the golden build. Also I don't think this would fix anything because the absence of video signal is during POST when OC has not been loaded yet.
e) done. always been enabled since I switched to OC v0.5.9 last year.
f) same as above
g) Not tried but again because the issue is at POST, I don't think that changing the SMBIOS will fix the issue
h) I have the same feeling that as per g), this would fix any issue if I had no video signal at all. But this is not the case. I don't have video signal during POST. If I switch on the system, I can see the LED on the monitor going from flashing to still upon hearing the beep which indicates video signal is coming, then it flashes meaning no video signal until it is still again and at this point in time macos is displayed on the screen. The boot time is the same one whether I see the POST video signal if I use an HDMI cable or just DP to DP. I just wait in front of a black screen for 20/30s and macos is up a running. It is just frustrating for the reasons mentioned in my post.
 
Joined
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Messages
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Gigabyte B550 Vision D
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Hi there,

Thanks for the help. Here are some comments:
a. Done. always been enabled. Part of the golden build guide.
b. don't have this option in my bios
c) already using it, even before installing the 6800XT
d) Can't have only this SSDT in ACPI. Need several SSDTs to fix wake/sleep, etc. As per above, part of the golden build. Also I don't think this would fix anything because the absence of video signal is during POST when OC has not been loaded yet.
e) done. always been enabled since I switched to OC v0.5.9 last year.
f) same as above
g) Not tried but again because the issue is at POST, I don't think that changing the SMBIOS will fix the issue
h) I have the same feeling that as per g), this would fix any issue if I had no video signal at all. But this is not the case. I don't have video signal during POST. If I switch on the system, I can see the LED on the monitor going from flashing to still upon hearing the beep which indicates video signal is coming, then it flashes meaning no video signal until it is still again and at this point in time macos is displayed on the screen. The boot time is the same one whether I see the POST video signal if I use an HDMI cable or just DP to DP. I just wait in front of a black screen for 20/30s and macos is up a running. It is just frustrating for the reasons mentioned in my post.

Ok. In that case you should at least try to add the device properties what I mentioned above into OC. The memory section is especially important - without it it simply will not boot (along with the agdpmod=pikera - they must be used together). As for b) that is the speed setting of Slot 1 ie. Gen 3/Gen 4 etc. It may come under Max Link Speed under Settings section. As for g) oh it does affect it. Some systems do & don't work with iMacPro1,1, likewise with MacPro20,1 and iMac19,1.
 
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