Mac Pro W6800 Duo and games/simulators in Windows

[AndreeOnline]

Does anyone have actual experience with a Mac Pro and dual GPUs, or dual Duos, when gaming in Windows?

Expectations here are low, but I'm just curious if "two", or in my case "four" GPUs can be used to max out gfx settings in 2024.

Assume Windows using Bootcamp as a base, but if there are additional drivers/tricks I'd be interested in that too, of course.

The Mac Pro currently doesn't even have Windows installed and gaming for this Mac is not a priority. But if it against all expectations works "sort of well", I might do some occasional flight simming. Interested in experiences both in MSFS and DCS World.

 

[Regulus67]

Hi AndreeOnline, this question intrigued me, so I did a search. And almost came up empty handed.

Seem like it might help in setups with many monitors. Manny
And BufordTX suggests editing the game profile. Might be worth a look?

 

[Irishman]

Does anyone have actual experience with a Mac Pro and dual GPUs, or dual Duos, when gaming in Windows?

Expectations here are low, but I'm just curious if "two", or in my case "four" GPUs can be used to max out gfx settings in 2024.

Assume Windows using Bootcamp as a base, but if there are additional drivers/tricks I'd be interested in that too, of course.

The Mac Pro currently doesn't even have Windows installed and gaming for this Mac is not a priority. But if it against all expectations works "sort of well", I might do some occasional flight simming. Interested in experiences both in MSFS and DCS World.

I’m not 100%, but I don’t think that SLI (like in the old days), is even a thing anymore.

 

[avro707]

Interested in experiences both in MSFS and DCS World.

If you can let me "borrow" your W6800X Duos then I can tell you how it works on MSFS.

I have a normal W6800X MPX and that runs MSFS reliably, far more than what I see on some other brands of GPU probably because it has 32GB VRAM where some other cards were running out of memory.

I use Windows 11 Pro for Workstations on my 7,1 and that runs nicely. MSFS is on DX12 mode.

I saw that architecture diagram for the Duos recently on the Mac Pro forum and wondered how it compares with the old days of SLI and similar (linking two cards together).

How do modern games see the W6800X Duo? As one card or as two separate ones?

 

[AndreeOnline]

Thanks for pitching in guys.

Like you Regulus67, I also started with some googling and I think I came across some of the content you and Irishman read. In the end, I guess I felt that the easiest way to some good intel, is simply to ask here because it seems likelier to find someone with updated software and recent experiences.

At least avro707 says he's got Win 11 Pro (not officially supported, I believe) and MSFS running well with a W6800X.

When it comes to CrossFire I wasn't sure if the Bootcamp drivers would do anything for me, in terms of how Windows "sees" the cards.

If anyone else reads with experience, please let us know. If I get around to installing Windows, I'll update this thread with my own data.

 

[avro707]

At least avro707 says he's got Win 11 Pro (not officially supported, I believe) and MSFS running well with a W6800X.

You have to do a bit of fussing about to get W11 installed but it runs well when it is done.

That's not an out of the box plane, that's the PMDG 737-700. The actual image does look a lot better than that at full resolution.

I haven't worked out yet how to video capture the VR view from my Reverb G2, if I could do that it would be pretty awesome - but I can say that it is incredibly immersive. Early morning flights from Melbourne (YMML) to Sydney (YSSY) are pretty amazing with the sunrise from the east, you almost get to the point where you think, damn, I need sunglasses - the impression of glare is quite good.

In general the feeling of height and being there inside the plane and in a real world is very good and I found it makes landing a lot easier than looking at a 2D screen.

And of course the other awesome thing is the Lockheed Darkstar Mach 10 jet from the Top Gun Maverick movie, it is in Flight Sim and it is incredible to fly it with VR, the heat effects at high speed and the view out the small side windows at very high altitudes is something incredible.

Personally, I'm holding out for two planes:

- the FlyByWire Airbus A380: videos of it have been seen already and it appears extremely realistic and sounds exactly like the real thing. I know the sounds I right because I fly on the A380 so much. It's one of the common planes in and out of my airport. More amazing, it appears like it will be free!

- Concorde: There is one already but to be honest the discussion from the dev about his plane didn't give me the impression of realism. I used to know the one in Flight Sim 10 which was a really full on systems simulation from a group who knew the plane inside out and had lots of contacts who worked on or flew the real thing. I imagine they might eventually move over to MSFS, at least I hope they will. That was a very rewarding thing to fly because of the accuracy of its systems. It didn't have GPS navigation, it used a proper Delco Carousel IV-AC and it had the climb performance and related systems behaviour spot on. Even things like engine surge if you were careless with retarding the throttles when beginning the slow-down from M2.0. I would love that in MSFS.

 

[diamond.g]

I’m not 100%, but I don’t think that SLI (like in the old days), is even a thing anymore.

D3D12 does support mGPU but no game (that I am aware of) supports it. Crossfire was discontinued in 2017, SLI was discontinued in 2020 (technically it was still supported on the 3090 and totally dropped in 2022).

 

[Regulus67]

AMD has this to say on multi-GPU operation
Last Updated: September 8th, 2023

 

[diamond.g]

AMD has this to say on multi-GPU operation
Last Updated: September 8th, 2023

Yeah to be clear AMD says that DX12 games the mGPU support is up to developers. mGPU for DX9-11 games is handled in their driver like how they did crossfire (it isn't called CF now). For the original question about MSFS, maybe mGPU would work with the DX11 renderer, but that is assuming they could get the Adrenaline driver/app to load on a W series card.

 

[avro707]

For the original question about MSFS,

It has both DX11 and DX12 modes. I am not sure if Microsoft did support multiple GPUs, they did have a new release just recently but I didn't get a chance to install it yet.

 

[avro707]

I upgraded to a W3275M CPU yesterday and had it running Flight Simulator in Windows 11 Pro for Workstations and the Reverb G2.

One caution note on Flight Simulator, you should NOT connect the Reverb G2 to the thunderbolt ports on the W6800X GPU. There seems to be some bug that causes crashes. It's better to connect via the USB-C ports on the Mac Pro.

This issue seems to also affect PCs and the USB-C on regular RX6800XT card using its USB-C port. That explains why the sim ran very smoothly and reliably in 2D mode. That wasn't an obvious issue to troubleshoot.

It runs absolutely smoothly now and no more crashes to desktop. I also noticed I could have the resolution higher as well without stuttering.

Our 2019 Mac Pros with the big MPX module cards should and do run Flight Sim well, we have a lot more video memory, lots of normal RAM and generally reliable components.

 

[avro707]

I am going to bite the bullet and find out how it runs, I'm going to install four GPUs, ie, dual W6800X Duos with 64gb each RAM. it's not going to be cheap but I want to max out my Mac Pro.


I was extremely pleased today using the W3275M and a single W6800X flying around Richmond (YSRI) and Sydney (YSSY) with the real weather on and in the dense cloud and rainy conditions with the addon F111 in VR mode, it ran very smoothly despite a lot of complaints from PC users about poor FPS with this plane.

 

[avro707]

Something else to watch out for and it might be worse with the W6800X Duo - the GPU temps.

The normal W6800X in the situations above actually gets up to 90ºC, that's too hot for my liking so I use Macsfancontrol to boost the fan speeds and keep the card cooler.

These cards only have the heatsink and whatever airflow the main case fans push through them which perhaps isn't the best solution.

 

[avro707]

Some rumours are that MSFS 2024 will be much better optimised for multi-core CPU operation in comparison with the current one which really doesn't do a lot and you should have a very fast single core performance.

So potentially a Mac Pro 2019 with a 16 core, 24 core or 28 core might work out quite well. Currently those AMD 5800X3D processors are the king for MSFS at the moment.

 

[avro707]

Does anyone have actual experience with a Mac Pro and dual GPUs, or dual Duos, when gaming in Windows?

I have tested Flight Simulator on my 2.5ghz 28 core machine with a single W6800X Duo card.

Result is Flight Simulator 2020 ran on GPU1 and GPU0 did nothing. You get the same performance as a regular W6800X MPX module. A single W6900X is most likely going to be faster.

So for gaming W6800X Duo (or two them) are not much use unless the game is actually designed to take advantage of multiple GPUs. MS Flight Simulator 2020 is not.

Since you are in Windows, you might as well just use the Nvidia RTX4090 which will demolish the Apple specific Radeon cards. it will be cheaper as well.

Let's see what 2024 Flight Simulator will do when it arrives.

 

[avro707]

I have now tested Flight Simulator with dual W6800X Duo cards with the fabric link.

All cards show up in Windows but there is no benefit in performance. As above, performance is still smooth at high detail levels but the frame rates are no different to a single GPU card.

Flight Sim just doesn't even make use of two GPUs, let alone four of them.

 

[Flint Ironstag]

Ashes of the Singularity is the only game I've ever seen light up multiple GPUs in resource monitor.

 

[Rimmsi]

I upgraded to a W3275M CPU yesterday and had it running Flight Simulator in Windows 11 Pro for Workstations and the Reverb G2.

One caution note on Flight Simulator, you should NOT connect the Reverb G2 to the thunderbolt ports on the W6800X GPU. There seems to be some bug that causes crashes. It's better to connect via the USB-C ports on the Mac Pro.

This issue seems to also affect PCs and the USB-C on regular RX6800XT card using its USB-C port. That explains why the sim ran very smoothly and reliably in 2D mode. That wasn't an obvious issue to troubleshoot.

It runs absolutely smoothly now and no more crashes to desktop. I also noticed I could have the resolution higher as well without stuttering.

Our 2019 Mac Pros with the big MPX module cards should and do run Flight Sim well, we have a lot more video memory, lots of normal RAM and generally reliable components.

Hi, what cpu did you upgrade from? A larger L cache should improve minimum FPS, but 28core has a lower maximum frequency.

 

[avro707]

Hi, what cpu did you upgrade from? A larger L cache should improve minimum FPS, but 28core has a lower maximum frequency.

Xeon W3245 16 core 3.2ghz.