Possible to use additional AMD GPU *internally* with 2019 Mac Pro via OEM 580X?
 
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Possible to use additional AMD GPU *internally* with 2019 Mac Pro via OEM 580X?  

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Frederico
(@frederico)
New Member
Joined: 1 year ago
 

Pardon me if this sounds dumb or this isn't the appropriate forum to ask (if not, any directions elsewhere would be appreciated).

[LONG; no easy tl;dr]

My question has a few parts:

1) Given that with the advent of Mojave, under macOS, it is possible to *natively* 'Prefer eGPU' via Finder, or, as in FCP or Davinci Resolve, etc., within the app's prefs (and that all this is also possible with Set-eGPU, obv.), do you think it will be possible under Catalina on Mac Pro 2019 to select an additional non-MPX *internal* GPU (e.g, aftermarket 5700XT or Vega, etc.), that has no display *directly* attached, but whose display(s) is(are) instead attached via Thunderbolt 3, otherwise driven by an OEM Radeon 580X?

2) If not using 580X MPX (which has only HDMI onboard and its DisplayPort(s) are routed via MPX to the Apple I/O and top-case Thunderbolt 3 ports), would it be possible using an OEM MPX card that sports onboard Thunderbolt 3 ports? (bear with me here; I know you're asking 'why bother, then?')

3) If not *natively*, might it be possible to leverage Set-eGPU or other such utilities/command-line options to prefer an extra, untethered GPU in this manner under macOS?

4) Ignoring macOS, might it at least be achieved under the aforementioned conditions under Bootcamp, if for nothing else than gaming?

Note: I am *not* talking about trying to leverage Crossfire (esp. under macOS); I absolutely want the primary GPU to be the (presumably more powerful, or better-suited) aftermarket card wherever possible, but without directly tethering a display to it, a la an eGPU using the internal display on a MBP or iMac.

Why? [skip if you can already answer in the affirmative re: above]

Background: I'm getting really itchy to pull the trigger, rather than waiting for the "Coming Soon" W5700X MPX GPU, which is looking to be my card of choice for my day job; and, if luck smiles on me with this PO, I may also score a Pro Display XDR, which can *only* be driven via Thunderbolt 3 (@6K), and, to date, AFAIK, is only able to be driven by an Apple OEM MPX card (please correct me if I'm wrong, and there are aftermarket cards now or announced that will directly drive this display); I also have an acquaintance who already bit with just the OEM 580X MPX GPU and PD XDR. 

I already own a Radeon VII (for PC), and am thinking about treating myself to a 5700XT (PC); my acquaintance has similar.

What I'm hoping for out of all this is that, if nothing else, I will get the extra compute power simply by installing a spare GPU in an empty 16x slot (of which I'm confident), and, as far as gaming goes, under both macOS and/or Bootcamp, that somehow the additional GPU can route itself back through the MPX card and out via Thunderbolt to the PD XDR, if chosen as a primary GPU.

Make sense?

The latter will be true whether I wait for the W5700 XT MPX or not; I expect it will be available as a separate purchase, as are the Vega cards. However, I will only get one chance for the boss to pay for this one, so must choose wisely.

If this isn't going to be remotely possible, I will probably have to simply hold out for the W GPU, if I'm to perhaps also enjoy the PD.

A famous Internet personality is also already in this boat (and is eager for decent to great Destiny 2 FPS at good/better/best settings without using a second display), and none of us really want to have a second display on the desk just for casual or occasional gaming (read: workday stress relief); we already have gaming rigs that we'd like to put in the closet or save for very serious gaming days.

My housemate gets great FPS and performance under both macOS and Bootcamp using an eGPU; but I absolutely do not want an eGPU for any reason. Not a lot of point to paying for an $$$$$ eight slot MP, just to hang a bunch of noisy crap on the back of it. (As for the potential noise of the extra GPU, I'm happy to entertain water cooling, personally, or explore modding the card to take advantage of passive cooling like the MPX modules have).

Thanks in advance for any direction or advice that meets the above scenarios, and your patience if you somehow got this far. (:

Cheers

F

To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.

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joevt
(@joevt)
Noble Member
Joined: 3 years ago
 

@frederico

#1 good question. In other words, does the option exist for secondary non eGPU GPUs?

#2 this seems to be the same question as #1 because there is no difference between Thunderbolt controllers used by the 580X or any other MPX card. The Thunderbolt controllers are connected to the MacPro7,1 the same way whether they are on the MPX module or on the motherboard or I/O card.

The XDR display can be connected via a single DisplayPort cable. 6K 60Hz 12bpc HBR2 with DSC from Nvidia RTX:
https://forums.macrumors.com/threads/apples-pro-display-xdr-on-one-nvidia-2080-ti-thru-the-gigabyte-titan-ridge-add-in-card.2209947/

The W5700X should have DSC. I'm not sure about the 5700XT. Probably?

But you might be missing some features without a Thunderbolt or USB connection.

There is a frame drop in gaming rendering on one GPU and displaying from another. This increase with resolution. But this frame drop should be less than what occurs using an eGPU.

Mac mini (2018), Mac Pro (Early 2008), MacBook Pro (Retina, 15-inch, Mid 2015), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case


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Frederico
(@frederico)
New Member
Joined: 1 year ago
 
Posted by: @joevt

The W5700X should have DSC. I'm not sure about the 5700XT. Probably?

But you might be missing some features without a Thunderbolt or USB connection.

There is a frame drop in gaming rendering on one GPU and displaying from another. This increase with resolution. But this frame drop should be less than what occurs using an eGPU.

Thanks for a very comprehensive answer, and the helpful link. If I may, I’d like to clarify a few things?

from all I’ve been able to read, the W5700X is definitely announced as supporting DSC (And some random quote I couldn’t verify calling it the first “true” Navi 7nm); Apple confirms DSC on its pages; but it could be weeks, or months before it ships, and possibly longer before Apple’s MPX version is available (though it was announced as “Apple-first”, so who knows). The 5700XT is showing DSC 1.2, but I can’t find the version number for the W model, so I really don’t know if a retail XT will still strangle the USB speed, but based on the link you provided, and your comment about features, it seems likely, no? If for no other reason than it only has DP and requires Titan Ridge to drive XDR?

Now, when you indicated a frame drop with two AMD cards installed, do you mean a drop from the best possible FPS with a single card, or a possible/probable combined, but not optimal increase overall? When I watch some of the eGPU videos, and listen to my roomie, they seem to indicate a healthy FPS/settings boost using an internal display, as on a MacBook Pro or iMac, albeit not as high as the better single card should deliver.  Have I misinterpreted here?

Thus, if I understand my choices, I can opt for $1200 + $100 ti/Titan combo, and have the best (currently) available gaming experience (on Mac), with some limitations using an XDR, but only under Bootcamp, and would require a cable swap at the display between OS boots; or I can live with whatever an MPX card can deliver on its own, or in concert with a (more affordable to me) AMD card offering increased performance for workday apps under macOS; and if I’m willing to cable-swap in the first place, I can add the Titan Ridge to it and game with less power (than nvidia) in bootcamp, with similar (likely) restrictions — up to and including not trying to game at 6K (lol). 

Or, I can forgo the idea of gaming on an XDR and instead deal with a second display (in too-cramped quarters), or forgo the XDR altogether, and live with 4K display until/unless somebody (are you listening, Apple?) offers a better 5K option than (not a fan of) the UltraFine; or forget about stress-relief gaming on workdays in the present company of friends, and just drag on with the adequate gaming PC I have for the non-hardcore gaming I enjoy. [sigh] 

and if I forgo the XDR altogether, I may as well get the cheapest 580X, and pour money into a better workstation card later, and live with 4K waiting for better 5K (or maybe even 6K) from somebody.

easy enough choices for me, since I’m not hardcore, but others with XDR and 580X already in hand aren’t likely to have an immediately great solution, yes? 

Many Thanks, thanks for letting me think out loud, and Happy Saturday 

F

To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.

.

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mac_editor
(@mac_editor)
Famed Member Moderator
Joined: 4 years ago
 

@frederico

Regarding #3, set-eGPU uses the same native prefer eGPU checkbox so there is inherently no difference. It is only applicable to eGPUs, which are treated differently vs. internal ones in macOS.

To use an internal GPU as the main GPU for rendering content while using a display connected to a different (presumably weaker) GPU, you may need to launch the application on a display connected to the other GPU. Since you don't want another display, use a headless/ghost adapter. Apps such as DaVinci Resolve and Final Cut Pro will allow you to choose your render/share GPU (no headless adapter needed), with the former allowing selection of multiple GPUs. Only on Mac Pro 2019, Final Cut Pro is supposed to also use multiple GPUs effectively.

purge-wranglertbt-flashpurge-nvdaset-eGPU
Insights Into macOS Video Editing Performance

Master Threads:
2014 15-inch MacBook Pro 750M
2018 15-inch MacBook Pro

 
2019 13" MacBook Pro [8th,4C,U] + RX Vega 64 @ 32Gbps-TB3 (Mantiz Venus) + macOS 10.14.6 & Win10 [build link]  


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joevt
(@joevt)
Noble Member
Joined: 3 years ago
 
Posted by: @frederico

so I really don’t know if a retail XT will still strangle the USB speed, but based on the link you provided, and your comment about features, it seems likely, no? If for no other reason than it only has DP and requires Titan Ridge to drive XDR?

With a USB-C with DisplayPort alt mode connection, 4 lanes of DisplayPort leaves only a USB 2.0 connection for the USB ports of the XDR. I think that should be enough to support all features (6K requires DSC, 5K would work only at 8bpc without DSC).

A Thunderbolt connection without DSC would also be limited to USB 2.0 speed.

Using a GC TITAN RIDGE would not give a USB connection because the GC-TITAN RIDGE would not support PCIe tunnelling unless the GC-TITAN RIDGE was connected by PCIe to your computer and software was available to enable PCIe tunnelling. A classic Mac Pro can do that by warm booting from Windows. Hackintoshes can do that with some SSDT additions. PCs running Windows shouldn't have a problem (Windows might allow HDR but won't have the presets - I don't know if BootCamp drivers enable other features for Windows).

I don't think the version of DSC matters. They all have at least a 3:1 compression ratio, allowing 6K60 to work at 12 bpc with just HBR2 speed.

I said there is a frame drop if a game is rendered on one GPU and displayed by a different GPU (the display is not connected to the GPU that is doing the rendering). It takes time to transmit the video rendered by one GPU to the display buffer of the other GPU. The frame drop is relative to the GPU doing the rendering. The GPU with the display connected has to do little work. The framerate may still be greater than what the other GPU can do by itself with the display connected to it (this is usually true for laptop GPUs except for laptops with extremely capable GPUs such as gaming laptops - the GPU in the new 16" MacBook Pro is pretty good by itself).

Nvidia cards only work in macOS up to High Sierra. New Macs can't run High Sierra. So you'll do your gaming in Windows if you're using an Nvidia card. In that case, you might as well get an RTX card which has a USB-C port so you don't need the GC-TITAN RIDGE.

On the AMD side, the Radeon Pro W5700 is not as powerful as the 5700xT but does include a USB-C port. The USB-C port should allow connecting the XDR without a GC-TITAN RIDGE. I believe it should work in macOS.

Gaming at 6K might be interesting. It depends on high the graphics settings are. I played WoW at 5K using a Maxwell based Titan X in macOS High Sierra. 6K is 38% more pixels than 5K though.

Mac mini (2018), Mac Pro (Early 2008), MacBook Pro (Retina, 15-inch, Mid 2015), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case


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