MP 7,1 Boot up from non-MPX Graphics Card?

[Rian Gray]

I don't know if any of the support documents mentioned it, but when I try booting up a Mac Pro with only a 3rd party graphics card (Vega 64), it won't give me any display signals. The only way I can get a proper display is with RX580X module installed. The MPX module itself is not connected to any monitors, and when I do check "About this Mac", I get Vega 64 (which is connected to a monitor) as the graphics card.

Is this an intended behavior? If not, where should I start looking?

On a side note, though Vega 64 is on a supported GPUs list, Expansion Slot Utility seems to be having trouble identifying it. It tells me current width of PCIe is only x8, when it is x16. System Report does give me x16 for the Vega, so I'm assuming it's just the utility having an issue. It didn't occur with a 3rd party RX580 card.

 

[OkiRun]

I don't know if any of the support documents mentioned it, but when I try booting up a Mac Pro with only a 3rd party graphics card (Vega 64), it won't give me any display signals. The only way I can get a proper display is with RX580X module installed. The MPX module itself is not connected to any monitors, and when I do check "About this Mac", I get Vega 64 (which is connected to a monitor) as the graphics card.

Is this an intended behavior? If not, where should I start looking?

On a side note, though Vega 64 is on a supported GPUs list, Expansion Slot Utility seems to be having trouble identifying it. It tells me current width of PCIe is only x8, when it is x16. System Report does give me x16 for the Vega, so I'm assuming it's just the utility having an issue. It didn't occur with a 3rd party RX580 card.

"You can use Radeon MPX Modules along with other third-party PCIe graphics cards."
I think the message is that you have to use them together.

 

[Rian Gray]

"You can use Radeon MPX Modules along with other third-party PCIe graphics cards."
I think the message is that you have to use them together.

Oh, that actually does make sense. And I suppose it also means it's an intended behavior then. Thanks!

What about the expansion utility? I know it's meant only as an assistant tool to automate some of the setups. Could it be some infos simply slipped through and didn't make it?

 

[erroneous]

Datapoint: I was able to boot up my Mac Pro with only a 5700XT Red Devil installed (original 580X MPX removed) and get boot up screen and normal display behaviour. The card has three DP ports, and one HDMI. I ran it with four monitors via two dp/dp cables, two hdmi/hdmi cables, and a displayport/HDMI adaptor.

I have recently removed the 5700XT and replaced it with a Vega II MPX module. The sleep problems, occasional crashes were very frustrating. The Vega II has its own quirks - when changing resolutions/rotation monitor settings it seems to take a long time to sync everything back up, so goes through a series of display resets. I can live with it.

 

[Rian Gray]

Datapoint: I was able to boot up my Mac Pro with only a 5700XT Red Devil installed (original 580X MPX removed) and get boot up screen and normal display behaviour.

I'm now more puzzled then before. Was there any additional steps like disabling SIP? It might as well be the simple case of compatibility issue though.

 

[erroneous]

I do not think I disabled SIP while I had the 5700xt installed.

I have since removed it and installed a Vega II MPX module, as I was experiencing regular sleep crashes and occasional green-screen failures with the 5700XT which eventually exceeded my patience.

 

[LEOMODE]

You can boot up using an external GPU only mode as bootup screen is now tied to a machine, not on a GPU. You do lose the top 2 thunderbolt ports though as they're feeding from MPX module (that's if you don't have one installed at the time you boot up).

 

[joevt]

You can boot up using an external GPU only mode as bootup screen is now tied to a machine, not on a GPU. You do lose the top 2 thunderbolt ports though as they're feeding from MPX module (that's if you don't have one installed at the time you boot up).

The only thing feeding from MPX module to the Thunderbolt ports of the Mac Pro is DisplayPort signals. The Thunderbolt ports should still work for non-display purposes when there's no MPX modules. You can connect an eGPU and connect a display to the GPU in the eGPU (this counts as a non-display purpose since the Mac communicates with the eGPU using PCIe, and it is the GPU in the eGPU that provides DisplayPort to the display).

 

[LEOMODE]

The only thing feeding from MPX module to the Thunderbolt ports of the Mac Pro is DisplayPort signals. The Thunderbolt ports should still work for non-display purposes when there's no MPX modules. You can connect an eGPU and connect a display to the GPU in the eGPU (this counts as a non-display purpose since the Mac communicates with the eGPU using PCIe, and it is the GPU in the eGPU that provides DisplayPort to the display).

Are you talking about 2 thunderbolt ports next to the power button?

 

[joevt]

Are you talking about 2 thunderbolt ports next to the power button?

Yes. The same applies to the two Thunderbolt ports on the I/O card. There's one Thunderbolt 3 controller for the top ports and another Thunderbolt 3 controller for the I/O card ports. Both take two DisplayPort signals from an MPX slot.

Some MPX GPUs provide two DisplayPort signals (Vega II, W5700X). I think the two signals can go to either set of ports. I don't know if you can get one DisplayPort to the top ports and the other DisplayPort to the I/O card ports.

Some MPX GPUs provide four DisplayPort signals (RX580, Vega II Duo) so that both Thunderbolt controllers get two DisplayPort signals.

 

[LEOMODE]

Yes. The same applies to the two Thunderbolt ports on the I/O card. There's one Thunderbolt 3 controller for the top ports and another Thunderbolt 3 controller for the I/O card ports. Both take two DisplayPort signals from an MPX slot.

Some MPX GPUs provide two DisplayPort signals (Vega II, W5700X). I think the two signals can go to either set of ports. I don't know if you can get one DisplayPort to the top ports and the other DisplayPort to the I/O card ports.

Some MPX GPUs provide four DisplayPort signals (RX580, Vega II Duo) so that both Thunderbolt controllers get two DisplayPort signals.

Interesting since I thought above 2 ports worked as USB-C type as well as for 6 displays, although I never tried connecting displays on the top 2 ports.

 

[joevt]

Interesting since I thought above 2 ports worked as USB-C type as well as for 6 displays, although I never tried connecting displays on the top 2 ports.

All the Thunderbolt ports can work as Thunderbolt or USB-C. Six displays (at least up to 4K max) can be connected to any six Thunderbolt ports as long as they have a DisplayPort path to a GPU. Of course, all the Thunderbolt ports of an MPX GPU have a DisplayPort path. The four paths to the I/O card and top ports are as I described above (0 of the four paths will exist if you do not use an MPX GPU; otherwise there could be a path for only two of the ports, or four paths for all the ports depending on the installed MPX GPU(s) installed).

 

[Rian Gray]

You can boot up using an external GPU only mode as bootup screen is now tied to a machine, not on a GPU. You do lose the top 2 thunderbolt ports though as they're feeding from MPX module (that's if you don't have one installed at the time you boot up).

How do I set it to eGPU only mode for boot up? It was my understanding cards supported for Mac eGPUs was already made capable of displaying boot screen. Right now I can boot up with my monitor connected to a 3rd party card, but not without an MPX module. I'm using DisplayPort to connect 'em, but I don't think MPX would be part of other graphics cards' connection from a DisplayPort (on card) to a monitor.

After searching through some of the older threads, I've found out that people have been exchanging their test results on the exact issues. It seems Expansion Utility doing this is a common problem, and doesn't seem to cause drastic issue. So I guess that part of the mystery is solved.

edit: I meant the expansion utility part, not the whole thing.

 

[LEOMODE]

How do I set it to eGPU only mode for boot up? It was my understanding cards supported for Mac eGPUs was already made capable of displaying boot screen. Right now I can boot up with my monitor connected to a 3rd party card, but not without an MPX module. I'm using DisplayPort to connect 'em, but I don't think MPX would be part of other graphics cards' connection from a DisplayPort (on card) to a monitor.

After searching through some of the older threads, I've found out that people have been exchanging their test results on the exact issues. It seems to be a common problem, and doesn't seem to cause drastic issue. So I guess that part of the mystery is solved.

i have never yet taken mpx out to boot but i did only connect cables on the aftermarket card and still was able to see the boot screen and boot off of aftercard.

 

[flowrider]

I have an Aorus RX5700XT and an LG UltraFine monitor with a USB-C input. I am using a bidirectional cable (USB-C to DP) and don't get a boot screen. My old monitor had a DP input and I got a boot screen with that setup. Over time I become frustrated with the lack of a boot screen. I reinstalled my OEM 580X above the 5700XT and ran the TB cable from the IO card to the second input on the monitor. I still get no boot screen with the 5700XT hooked up. When I pull the cable for the 5700XT from the monitor it boots from the 580X with a boot screen.

Lou