MP 1,1-5,1 cMP 5.1 (Ventura with OCLP 1.2.1) with AMD RX Vega 56 with problems.

[ZNDK]

I'm using AMD RX Vega 56 nano edition. I changed from RX580 to it and have had a few glitches since the change.
My Mac is Ventura 13.6.1 with OpenCore Legacy Patcher 1.2.1 (OpenCore 0.9.6).

1 - Sleep wake up problem
When the Mac goes to sleep using any method and then wakes up(Front white LED is changing from slowly blinking to always on), the Mac is waking up but cannot display anything. At this time I assume that the Mac is frozen because no error sounds, etc. are made when I hit the keyboard at random.
I had the same condition when I used RX580 before. At that time I was able to work around it by disabling reopen and setting pmset gpuswitch, but these do not work for Vega 56.

2 - Shutdown Failure
When I restart my Mac normally, and when I quit and cold start it, both times I get a dialog box saying that "You shut down your computer because of a problem" when I started it.

3 - Color when switching screens
The entire green color is displayed for a moment just before the image appears on the LCD screen, such as at startup.

4 - Slowing down of display behavior
I do not know the trigger of the occurrence, but when I start the Mac, sometimes it is normal and sometimes it is abnormal. When the Mac starts up, all movement displays are sluggish except for the mouse cursor movement, as if the Mac is running heavy in the background. Of course, nothing is working in the background.

Is there any way to resolve these?

 

[ZNDK]

There are also new problems.
5 - Difficult to start Mac
I adjusted the memory card and the anomalies began to appear after that. When I turned it on, the white LED on the front kept on all the time and would not start without a startup sound. Or it can boot normally. This occurs on cold boot and not on reboot. What is odd is that it occurs even when the system is started without a single memory card pointing to it. Normally the white LED on the front would flash if the memory is 0, but it does not. The LED stays on all the time even if the memory is 0.

6 - power being turned off
When I try to launch certain applications, the MP immediately turns off. After that, cMP cannot be started without performing an SMC reset.

 

[tsialex]

Did you run ASD to see if your Mac Pro does not have any hardware issues? Which problems you have when booting a fully supported macOS release?

 

[ZNDK]

Did you run ASD to see if your Mac Pro does not have any hardware issues? Which problems you have when booting a fully supported macOS release?

I don't have ASD so I ran AHT and found no problems. The 48GB of memory affected 6 hours of use. cMP's memory verification with Memtest86 took 11 hours.

I can install Mojave on HDD and reproduce the problem with only one configuration of it. There is no HDD for Snow Leopard, but there is a USB flash drive installer. It reproduces even if internal HDD is set to 0 and only USB flash drive boot is available. Currently I don't have a HDD that can install Snow leopard and can't try.

I have yet to find an application in Mojave that shuts down cMP abruptly. I reverted back to RX580 and it did not occur.

An even stranger phenomenon is occurring. When I unplug the power cable from the MP (no matter how long I leave it) and plug it back in, the MP automatically turns on. So I am unable to do an SMC reset?
The only time I would be able to do an SMC reset is when its suddenly powered off.

 

[krakman]

I reverted back to RX580 and it did not occur.

To me this suggests the problem is with the Vega 56 card.

I have a cMP 5.1 with Vega 56 + OCLP + Monterey. It is rock solid.

How have you installed the Vega 56?

Are you using a EVGA powerlink to smooth out the power draw?

Is there a normal/high performance switch on the side of the Vega card?

 

[ZNDK]

How have you installed the Vega 56?

My Vega 56 is Nano edition. There is no switch to adjust this.

Are you using a EVGA powerlink to smooth out the power draw?

No.

 

[krakman]

My Vega 56 is Nano edition. There is no switch to adjust this.


No.

Are you using two power cables to the GPU?

The spec says 1x 8pin.

You should have both mini 6pin power plugs going to one 8 pin or 6 pin plug.

Or better still…. two mini 6 pin >> EVGA powerlink >> vega nano

My bet is the Nano is causing the shutdowns by drawing too much power through one cable.

 

[ZNDK]

You should have both mini 6pin power plugs going to one 8 pin or 6 pin plug.

The Vega 56 nano edition is 6 pin and 8 pin. So I am converting one of the 6 pin cables from MP to 8 pin.

 

[tsialex]

The Vega 56 nano edition is 6 pin and 8 pin. So I am converting one of the 6 pin cables from MP to 8 pin.

This is not sufficient, even more so with a GPU that does not have the power save mode switch. You will have SMC cutouts and crashes.

8-pin = 150W, MacPro5,1 can provide at best around 110W/115W with a mini-PCIe 6-pin power connector.

 

[Macschrauber]

When I unplug the power cable from the MP (no matter how long I leave it) and plug it back in, the MP automatically turns on. So I am unable to do an SMC reset?
The only time I would be able to do an SMC reset is when its suddenly powered off.

This points to an empty rtc battery

 

[alvin_vancouver]

This is a similar issue I had with MSI vega 64 on mac pro 5,1 + OCLP + Monterey. The cause is the temperature of the vega 64 goes as high as 71C even at idle, leading to issues including low performance and rebooting. The reason behind is the fan control of the hardware is incompatible with mac os's driver which is designed specifically for those build-in vega cards come with certain model of macs. The solution is add a kext into the opencore to correct the fan control behaviour and set the target temperature for the fan. I set it to 50C and it has been working flawless since then including gaming.

Your problem might be not related to this, but you can have a look by installing HWMonitorSMC2 and check out the GPU temperature.

MP 1,1-5,1 Vega 64 high temperature on idle and the resolution​

Vega 64 high temperature on idle and the resolution

There has been a common issue for Vega cards on classical Mac (4,1/5,1) running BigSur/Monterey: the fan is not spinning fast enough on idle, leading to an unreasonable high temperature (~75'C). In many posts, it is assumed to be acceptable, and was advised to do nothing. However, it is just too...

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