Oxide games interview - DX12 & Multi GPU details

[CommandMan7]

Tom's hardware has conducted an interview with Dan Baker of Oxide Games, the creator of the Nitrous Engine. Nitrous Engine is one of the first engines to implement DX12 features at all levels, and is currently being used to develop the game Ashes of the Singularity. A few months ago, news broke that Nitrous engine would eventually support not only traditional multi-GPU setups, but cross-vendor GPU setups as well. This announcement generated much attention from the tech crowd, and left the public with many unanswered questions.

 

First of all, will iGpu + dGpu setups be possible?

 

 Baker says that it will eventually be possible - 

 

 

 

for example, pairing the new Intel Iris Pro integrated graphics with a comparable discrete GPU would work very well, but two GPUs that don’t share similar performance characteristics adds a whole new level of complexity to the engine but he believes this is completely feasible. “We’re convinced we can make good games on it,” he said.

 

This means that although difficult, highly different performing GPU's, including iGpu's, will be able to work in multi-gpu setups confirmed.

 

On the topic of cross-vendor GPU support, 

 

 

 

Baker noted that they are currently very much in the experimental stages of figuring out how DX12 can be used with multiple GPUs from different vendors. He said that in many cases, Microsoft doesn’t have the answer to their questions, so there’s been much trial and error between the two companies to get things to work.

 

However,

 

 

 

He was reluctant to say when we’d see a public release, but he did confirm that the company intends to have it working during the beta period of Ashes of the Singularity.

 

This means that multi-vendor support is confirmed.

 

Baker also explained why these new multi-gpu features are even possible at all. It's all thanks to a new method to make use of multi-gpu setups: Explicit Linked Multiadapter. What is Explicit Multiadapter? 

 

 

 

Explicit Multiadapter doesn’t require a software driver to use multiple processors. It also treats multiple GPUs as seperate GPUs. 

 

Baker also goes on to say that Explicit Multiadapter also allows for much better scaling and better memory sharing. He also emphasized that

 

 

 

linked GPUs don’t need to have specific driver profiles for SLI and CrossFire as long as the GPU complies with DX12 specifications. He said the profile is essentially meaningless with DirectX 12, as the driver doesn’t even know that the game is using two graphics cards.

 

Although general driver optimizations will still have to be made, there will be no special effort needed for Multi-GPU setups on DX12. This means all dx12 games will have multi-gpu support.

 

One of the highly anticipated DX12 features, memory pooling, has not yet been implemented, and for good reason.

 

 

 

Baker said that the current build of the Nitrous Engine uses duplicated resources for each GPU because of bandwidth constraints. He went on to explain that for Explicit Multi-GPU to share resources, the data has to be accessible by both GPUs -- meaning it needs to go into system memory. Because of the bandwidth constraints of system memory compared to the throughput of GDDR5 and HBM, the company opted to use duplicated memory resources. However, Oxide has not yet written off the idea of using a shared memory pool in some cases, and the company has some ideas about how to use two independent memory pools to its advantage.

 

This means that although it's generally considered to be a low priority, memory pooling is still possible and  is under consideration for use.

 

One of the unforeseen improvements that exists in Nitrous engine that specifically brings more general performance was also detailed: Object Space Rendering. It essentially renders in reverse order of current GPU's: It removes aliasing and noise before adding any detail to the scene. Baker says

 

 

 

Baker and his team started off trying out the Object Space Rendering technique as an experiment. He said they didn't plan to use it, but after they started testing it out, they realized that it can be scaled up and down easily to suit different hardware profiles. The Nitrous Engine can control the number of shading samples that the entire scene has to work with so it can be scaled to suit any graphics hardware, including integrated GPUs. Baker said that Object Space Rendering is more work overall, but that "it’s actually very efficient to use hardware in this way. Even though we have to do more overall work, the GPU is being used at a higher percent of efficiency."

 

This means that although not a DX12 feature, Nitrous engine may bring large improvements in overall performance.

 

Bakers closes by saying this:

 

 

 

Oxide Games and the Nitrous Engine are just the pioneers of an industry-wide change in how graphics are rendered in the future. He was reluctant to elaborate, but when I asked if he thought this will be used in VR, he allowed, "I would say yes."  

 

Personally, I am really once again excited for DX12. Although memory pooling seems to be a long shot, Multi-gpu systems are finally getting the love they deserve. Looking forwards to hearing more about this. 

 

Sorry for the long post, I wanted to break the article down in an easy-to-understand way. 

 

Source: http://www.tomshardware.com/news/oxide-games-dan-baker-interview,30665.html

[qwertywarrior]

pretty cool but at the end devs are lazy as F*** we will rarely see any one make full use of such capabilities 

[Misanthrope]

“We’re convinced we can make good games on it,”

 

highly different performing GPU's, including iGpu's, will be able to work in multi-gpu setups confirmed

 

Umn no, that's not at all confirmed or even he confirming they will be able to, at best he's optimistic.

[OSBK]

really cool, i think i'll get windows10 soon and i'll put in my old GPUs for some test to see if it's true

[lightningterror]

This will make the igpus a bit more useful. I estimate a boost of 10-30% gaming performance.

[SolarNova]

DX 12 great.

 

Alas, game Devs wont be using it for the same reason they rarely use DX11 and still use DX9. DX9 is 'easier'.

 

I hope im wrong, I would love to see a proper shift to a new API like DX12, to final get optimised games.

 

But along with DX9 being easier, its likely that console ports will also be easier to port using DX9 than DX12, so once again PC users will get shafted thanks to those crap consoles.

[Belgarathian]

Pretty sure this is all old news.... Anandtech did a write up of it here. 

[Belgarathian]

DX 12 great.

 

Alas, game Devs wont be using it for the same reason they rarely use DX11 and still use DX9. DX9 is 'easier'.

 

I hope im wrong, I would love to see a proper shift to a new API like DX12, to final get optimised games.

 

But along with DX9 being easier, its likely that console ports will also be easier to port using DX9 than DX12, so once again PC users will get shafted thanks to those crap consoles.

 

Xbox One is DX12 now with the November update?

[ManIkWeet]

Although general driver optimizations will still have to be made, there will be no special effort needed for Multi-GPU setups on DX12. This means all dx12 games will have multi-gpu support.

No, this means that all games could theoretically make use of multiple GPUs if the developers decide to implement it, which they won't because time constraints and pushy mean publishers...

[DEDRICK]

DX 12 great.

 

Alas, game Devs wont be using it for the same reason they rarely use DX11 and still use DX9. DX9 is 'easier'.

 

I hope im wrong, I would love to see a proper shift to a new API like DX12, to final get optimised games.

 

But along with DX9 being easier, its likely that console ports will also be easier to port using DX9 than DX12, so once again PC users will get shafted thanks to those crap consoles.

 

Consoles are more similar to DX12/Vulkan than DX9/DX11, that is why we have shitty ports.  They make the game for console and have to port it to a strict API like DX9/DX11

[SolarNova]

Aye very true. Consoles games have a more direct connection to the hardware, where as PC games have to use an API.

 

However my point was, and truthfully I didn't make it very clear, that DX9 although more different than Consoles games vs DX12, is still easier for Dev's to code, because they have used it for so long.

 

I bet we will still see console ports using DX9 long after DX12 has been out long enough to become mainstream if Dev's would have adopted it.

[Curufinwe_wins]

No, this means that all games could theoretically make use of multiple GPUs if the developers decide to implement it, which they won't because time constraints and pushy mean publishers...

This^

 

Massive difference.

[Zah]

This^

 

Massive difference.

 

 

No, this means that all games could theoretically make use of multiple GPUs if the developers decide to implement it, which they won't because time constraints and pushy mean publishers...

However, this now means instead of us having the blame the GPU maker (NVIdia and AMD) we can now direct our hate collectively to one entity who is easier to persuade:  The developer.

[Curufinwe_wins]

However, this now means instead of us having the blame the GPU maker (NVIdia and AMD) we can now direct our hate collectively to one entity who is easier to persuade:  The developer.

LOL We already direct hate at devs and they never change, because regardless of how much fuss people make, so long as they buy the product no one gives a shit (AKA Michael Bay movies).

[Dabombinable]

GTX 970+GTX 650ti OC 2GB+Intel HD4600+what ever single slot graphics card I can dig up=win?

Consoles are more similar to DX12/Vulkan than DX9/DX11, that is why we have shitty ports.  They make the game for console and have to port it to a strict API like DX9/DX11

So.....consoles technically already have all of the benefits of DX 12/Vulcan, ergo they won't see improvements if they were used.

[BuckGup]

CAN'T HEAR YOU OVER VULKAN! I really want Vulkan as I never will use that thing called Window 10 again.

[Dabombinable]

CAN'T HEAR YOU OVER VULKAN! I really want Vulkan as I never will use that thing called Window 10 again.

Vulkan still hasn't been finalised though-so we are stuck with the PITA that are Windows 7 through 10.

[MoonSpot]

@CommandMan7, please correct post for night theme users.

[BuckGup]

Vulkan still hasn't been finalised though-so we are stuck with the PITA that are Windows 7 through 10.

I just don't want it to take too long that all devs go to DX12 because it is here now and that equals profit

[Dabombinable]

I just don't want it to take too long that all devs go to DX12 because it is here now and that equals profit

Do you remember how long it took DirectX 11 to be implemented? And at any rate we still don't have powerful DirectX 12 graphics cards, the cards that support a new API first always have the worst performance when compared to successive cards that are designed with the new API in mind.

[HalGameGuru]

 

 

Umn no, that's not at all confirmed or even he confirming they will be able to, at best he's optimistic.

It has already been demoed as working. Disparate GPU's being used concurrently can happen, its just a question of devs supporting that performance disparity.

[Misanthrope]

It has already been demoed as working. Disparate GPU's being used concurrently can happen, its just a question of devs supporting that performance disparity.

 

Again, DEMO. Like those fucking doctored E3 demos? Yeah those might as well be pre-rendered.

[EChondo]

I already use my iGPU for QuickSync purposes(OBS), so my single GPU isn't going to get any help with DX12 at the moment.

 

This is promising news, but we'll see what happens in 1-2 years from now and how this will be implemented. We all hope this will be implemented by all devs, but we all know that won't be the case based on current issues at hand.

[HalGameGuru]

Again, DEMO. Like those fucking doctored E3 demos? Yeah those might as well be pre-rendered.

You have a game engine running stably rendering different parts of the frame on different GPUs, one of which is an iGPU, and the game operates. If a dev can get it working for a demo they can't do the same in the end product? DX12 lets you customize your render, you could use iGPU solely to render background mattes or NPCs. Like I said, its up to the dev to decide how to make use of that disparate GPU power, if at all.

[Inkz]

I would love to gain a few extra FPS from my iGPU that is just sitting there.