MP 7,1 MPX Vs Off-the-shelf GPUs

[mattspace]

Just wondering if folks could chime in on the differences between an MPX Vs. an Off-The-Shelf GPU that may not seem obvious.

Stability has obviously been something that seems to have bounced around a bit.

The MPX 6800 having double the VRAM of the retail one, for example is obvious. But what are the things to look for in display support, the system stealing display capacity to route to the built-in ports, what provides a better DisplayPort experience - a retail card or the DP alt mode in a TB port etc.

 

[prefuse07]

I know Linus from linustechtips mentioned some of the pros of it in some of his Mac Pro videos, I remember him saying something akin to this: if you double-stack MPX modules (imagine 2x), the Mac Pro's architecture allows the system to double and couple them together, meaning, if you wanted to have 128GB of total VRAM, you could only achieve that by utilizing 2x MPX modules instead of 2x discrete GPUs. I believe the GPUs are limited to 96GB total VRAM or something around that. Something about the AMD infinity fabric link.

The other part he mentioned too is that the Mac Pro power system is more optimized for MPX modules, meaning that dual MPX modules will function more efficiently than discrete GPUs, from a power/wattage standpoint.

Hope that helps.

 

[TrevorR90]

Compatibility issues with the XDR display

My off the shelf 6900xt did not play nicely with my XDR display, and for that reason, I returned the 6900xt. The workaround is to keep the 580x in the Mac Pro but if you use bootcamp (Which I do extensively), for some reason, you can't have 2 AMD cards

 

[prefuse07]

Compatibility issues with the XDR display

My off the shelf 6900xt did not play nicely with my XDR display, and for that reason, I returned the 6900xt. The workaround is to keep the 580x in the Mac Pro but if you use bootcamp (Which I do extensively), for some reason, you can't have 2 AMD cards

This may help

 

[mattspace]

Something that's really an edit for my original post, of course the MPX 6800 has the same vram as the Radeon Pro W6800, that has 6 displayport outputs. Don't suppose anyone has a link to whether that card works properly in a 7,1?

 

[goMac]

I know Linus from linustechtips mentioned some of the pros of it in some of his Mac Pro videos, I remember him saying something akin to this: if you double-stack MPX modules (imagine 2x), the Mac Pro's architecture allows the system to double and couple them together, meaning, if you wanted to have 128GB of total VRAM, you could only achieve that by utilizing 2x MPX modules instead of 2x discrete GPUs. I believe the GPUs are limited to 96GB total VRAM or something around that. Something about the AMD infinity fabric link.

Only if the MPX modules support Infinity Fabric (not all do.) It also won't double the VRAM. It's kind of like Crossfire in cards that support it.

The 6800 MPX module does support Infinity Fabric so you could get two and link them - as long as your software supports Infinity Fabric linked GPUs.

 

[randy85]

My experience is totally good and cool from using a Gigabyte 6800 XT alongside my original W5700X MPX module. It's stable as hell and performs quite nicely in Resolve. I kept the MPX module to drive my Pro Display XDR so I haven't encountered problems with display connectivity.

The only thing to be aware of is the fans making some sound if you do really heavy tasks (e.g. NR in Resolve).

I haven't tried the 6800 XT on its own, however I imagine it would be fine seeing as I never get any crashes running the two cards simultaneously.

 

[ZombiePhysicist]

Compatibility issues with the XDR display

My off the shelf 6900xt did not play nicely with my XDR display, and for that reason, I returned the 6900xt. The workaround is to keep the 580x in the Mac Pro but if you use bootcamp (Which I do extensively), for some reason, you can't have 2 AMD cards

On the other hand, the MPX modules can't drive an 8k display HDMI display. So if you want to slum it with the 6k XDR you would go with the MPX module, but if you want 8k, you'd go off the shelf. Depends what you're looking for.

 

[mattspace]

Just rebumping this to check if anyone knows why the MPX w6800 is only quoted by Apple as supporting 3 x 5k displays, when the Radeon Pro 6800 standard pci card lists support as 6 x 5k

I can't think of anyone doing a standalone non-thunderbolt 5k display at the moment, unless they're angling towards the ultrawide 5k displays?

 

[avro707]

Just rebumping this to check if anyone knows why the MPX w6800 is only quoted by Apple as supporting 3 x 5k displays, when the Radeon Pro 6800 standard pci card lists support as 6 x 5k

I can't think of anyone doing a standalone non-thunderbolt 5k display at the moment, unless they're angling towards the ultrawide 5k displays?

Might be the ultrawide displays rather than our LG Ultrafine 5K or the Apple 5K. I only have a 4K and 5K LG display, but if someone can send me 5 more 5K displays I'll glady test them. (can I keep them!)

It can do 3x 6K XDR displays I know that.

In my country I haven't seen any 8K displays on sale by anyone, not the Dell either.


Can a W6800X Duo MPX be added alongside a W6800X MPX 32GB? I'm planning on adding a second MPX module.

 

[mattspace]

Might be the ultrawide displays rather than our LG Ultrafine 5K or the Apple 5K. I only have a 4K and 5K LG display, but if someone can send me 5 more 5K displays I'll glady test them. (can I keep them!)

The stats on the AMD card are 6 x the standard 1440p HiDPI, so clearly that's what the have in mind... presumably because that's what DP 1.4 supports, but if the only on-the-market 5k displays are TB ones, it's kindof academic

It can do 3x 6K XDR displays I know that.

In my country I haven't seen any 8K displays on sale by anyone, not the Dell either.

Dell .au tend to not carry the full product range, and they've never offered the 8k display here.

The MPX one can do 3x6k, but only 2 of them can be plugged into the card, the other has to be in the IO card, or the top (plugging displays into the top of a machine is SO janky).

Can a W6800X Duo MPX be added alongside a W6800X MPX 32GB? I'm planning on adding a second MPX module.

AFAIK you can only infinitylink identical cards - Duo & duo, single & single.

 

[DrEGPU]

Just wondering if folks could chime in on the differences between an MPX Vs. an Off-The-Shelf GPU that may not seem obvious.

Stability has obviously been something that seems to have bounced around a bit.

The MPX 6800 having double the VRAM of the retail one, for example is obvious. But what are the things to look for in display support, the system stealing display capacity to route to the built-in ports, what provides a better DisplayPort experience - a retail card or the DP alt mode in a TB port etc.

VRAM, TB graphics output, silent-ish operation, no need for over-priced belkin accessory power cables, and perhaps most salient of all: guaranteed physical compatibility!

 

[mattspace]

VRAM, TB graphics output, silent-ish operation, no need for over-priced belkin accessory power cables, and perhaps most salient of all: guaranteed physical compatibility!

• Same VRAM as the 6800 Pro, which is what I should have compared it to.
• TB graphics output... so that's the LG5k and Apple displays, not a great loss if you want to use serious colour displays EIZO / NEC etc... and you have to plug a display into the top of the machine to drive 6 screens.
• How loud is the normal AMD card, compared to (presumably higher ramp the front fans would require to cool) the MPX version.
• The compatibility thing, yeah that's a good question - the 6800 pro hasn't been listed as an eGPU compatible card yet, and from what folks have said here, AMD don't seem to consider it mac-compatible.

 

[DrEGPU]

• Same VRAM as the 6800 Pro, which is what I should have compared it to.
• TB graphics output... so that's the LG5k and Apple displays, not a great loss if you want to use serious colour displays EIZO / NEC etc... and you have to plug a display into the top of the machine to drive 6 screens.
• How loud is the normal AMD card, compared to (presumably higher ramp the front fans would require to cool) the MPX version.
• The compatibility thing, yeah that's a good question - the 6800 pro hasn't been listed as an eGPU compatible card yet, and from what folks have said here, AMD don't seem to consider it mac-compatible.

Actually I meant that MPX cards are designed to physically fit inside a Mac Pro. Several GPU’s are simply too long to jam into the case

 

[avro707]

I saw in another topic with a firmware flash, the W6800X standard AMD card is now working on MP5,1. So I’d guess it will work in 7,1 also.

The MPX 6800X is totally silent running. In any situation the computer never makes a noise.

 

[chfilm]

are the early day issues of spinning up fans when the Mac goes to sleep in off the shelf cards a thing of the past now?

 

[ZombiePhysicist]

are the early day issues of spinning up fans when the Mac goes to sleep in off the shelf cards a thing of the past now?

My 6900XT does not exhibit that behavior. It will spin up when taxed though.

 

[mattspace]

Another thought I'd had about MPX Vs. AMD-inhouse w6800.. what version of Displayport do the MPX versions do when plugged in to a DP display. I know Thunderbolt only encapsulates DP 1.2, but does the port alt-mode to 1.4 when a Displayport display is connected, eg via a type-c to DP cable, or via a type-c to DP adapter?