Witcher 3 Physx GPU

[JigMcGalliger]

I just checked using NVidia control panel's visual indicator. Even with 660Ti dedicated to Physx, the game is running Physx off the CPU. Anyone know how to fix this glaring problem?

CDPR said it would support GPU Phsyx from the start:
http://physxinfo.com/news/11558/the-witcher-3-will-support-gpu-physx-now-officially/

 

[renz496]

Is there any option to enable gpu physx from in game setting? Anyway try enabling Hairworks. Also you need to understand that not all physic calculation will be done using gpu. Some of the calculation will always done on cpu. Only the feature that is accelerated by gpu will use gpu.

 

[JigMcGalliger]

You can't enable or disable Physx in the settings. Lots of features in the game use Physx, like the spells particles, so it is running at all times (they use it as a full middleware, not just an addon). I currently run HairWorks for Geralt only because full HairWorks drops me below 45fps; the three HairWorks settings are Off, Geralt, or Full (which means enemies and NPCs run HairWorks).

 

[17seconds]

The Witcher 3 uses CPU PhysX only. You're welcome, AMD fans.
http://www.geforce.com/whats-new/guides/the-witcher-3-wild-hunt-graphics-performance-and-tweaking-guide#the-witcher-3-wild-hunt-physx

 

[renz496]

^so all those particle, cloths and destruction are no longer accelerated by gpu? So does hairworks using gpu or cpu for hair simulation? All i know they did use tessellation to render hair/fur.

 

[17seconds]

Apparently Hairworks uses the GPU, but no in the same way that GPU PhysX uses the GPU CUDA cores. GPU PhysX uses CUDA acceleration, which is not a part of an AMD GPU. Hairworks doesn't rely upon CUDA processing in the same way.

The problem with AMD cards and Hairworks is that they are not as good at rendering tessellation. Each strand of hair is tessellated with Hairworks enabled. This impacts AMD GPUs more than Nvidia. The workaround is to reduce your AMD GPU's tessellation settings on an individual game profile within the Catalyst Control Center. This will allow you to enable Hairworks on an AMD GPU with minimal impact, but reduced image quality (barely noticeable).
http://wccftech.com/witcher-3-run-hairworks-amd-gpus-crippling-performance/

 

[renz496]

So does it mean hairworks use direct compute instead of CUDA?

 

[17seconds]

So does it mean hairworks use direct compute instead of CUDA?

Not sure, but isn't tessellation a function of specific tessellation hardware within the GPU? You know more about this stuff than I do.

 

[JigMcGalliger]

I think hairworks must use a combination. The tessellation makes the strands wider and more like actual hair (I think they are actually tesselating a flat model... times 100,000, the same thing they do for GrassWorks), while Physx give those models movement (they can set the hair to static, so there is no movement). Meanwhile they don't specify if this movement calculation is done on the CPU or GPU... except for the fact that the physx driver will only note the CPU.

 

[renz496]

Usually cloth and destruction were accelerated using gpu. But from nvidia own explanation it seems that this time instead of gpu they use cpu to do all the calculation. Probably because of PhysX 3.0?

 

[JigMcGalliger]

Yes, Physx 3.x is designed to be leaner, as well as working on processor architecture other than CUDA. Metro Redux, for instance, was built using Physx 3.x, but was released before Nvidia came out with those Physx drivers, for a time players would take the physx dlls from Daylight to get GPU Physx. So the game was forced to run on the CPU for the first week after release, though after that, no issues. 3.x does work better on CPUs than earlier iterations, but it still doesn't surpass the GPU/PPU setup in terms of performance relief. So this is just another developer not offering what they said would be offered... for pretty much no reason this time.

 

[renz496]

I think in early builds they probably intend to use gpu physx. I think CDPR mention once that they intend to use dynamic smoke but in the end they decides to can the idea because of the performance impact. I think it is good if they can improve PhysX performance on cpu. The thing that right now crippling AMD performance when hairworks being enabled most probably the heavy tessllation being used on the hair/fur

 

[17seconds]

There was a lot of news and reports about GPU accelerated PhysX in the Witcher 3 leading up to release. They even indicated such on a slide at an E3 presentation. It seems like they compromised a bit for some reason, I guess to sell more games somehow.
http://physxinfo.com/news/11558/the-witcher-3-will-support-gpu-physx-now-officially/

 

[JigMcGalliger]

That doesn't mean they can't patch the PC version for Nvidia users. Though don't hold your breath.

 

[17seconds]

That doesn't mean they can't patch the PC version for Nvidia users. Though don't hold your breath.

I'm actually hopeful of that happening. Seems like the code might be there for GPU acceleration.

So how's the game?

 

[JigMcGalliger]

Runs like crap, TBH... even on a 980 + 660Ti w/ 8350.

I almost want to say it is an adult version of Ocarina of Time (not in terms of story, just mechanics), meanwhile a witcher in this one is essentially just a Jedi from KoTOR.

 

[maxalge]

Runs like crap, TBH... even on a 980 + 660Ti w/ 8350.

I almost want to say it is an adult version of Ocarina of Time (not in terms of story, just mechanics), meanwhile a witcher in this one is essentially just a Jedi from KoTOR.

Open the rendering.ini file in the gamedir\bin\config\base

change HairWorksAALevel=8 to 1 or 2.

You should also play with tessellation levels, set it to 8x for a good compromise.

 

[renz496]

Even Nvidia own performance tweak guide mention that there is no gpu physx. So i doubt adding dedicated physx card will improve performance.

 

[Eggz]

This is the worst news ever! Well, not literally, but it really sucks.

PhysX is a graphics function, so it should be able to run on a graphics processor! Nvidia puts the tech on their GPUs, and a lot of people have dedicated PhysX cards like I do. The difference between Hairworks on and off is about 30 FPS on my 780 ti at 1080p. If I could offload that to my 750 ti, it would have been able to maintain most if not all of that additional 30 FPS. But instead the game plays like crap on a very high-end system. Fail!

 

[renz496]

This is the worst news ever! Well, not literally, but it really sucks.

PhysX is a graphics function, so it should be able to run on a graphics processor! Nvidia puts the tech on their GPUs, and a lot of people have dedicated PhysX cards like I do. The difference between Hairworks on and off is about 30 FPS on my 780 ti at 1080p. If I could offload that to my 750 ti, it would have been able to maintain most if not all of that additional 30 FPS. But instead the game plays like crap on a very high-end system. Fail!

well if anything else the core of PhysX rely on CPU (mostly). only few simulation that is can be very taxing to CPU were made to run on GPU. but today CPU is quite capable and nvidia have improve CPU PhysX a lot (especially with PhysX version 3.x.x). probably why developer like Bohemia Interactive willing to delay ARMA 3 in favor of nvidia finishing PhysX 3 and CDPR themselves replace havok (Red Engine 2) with PhysX 3 (Red Engine 3). even Project Cars only using CPU based PhysX in their game.

 

[17seconds]

I did just read that Unreal Engine 4 is incorporating the latest PhysX version, so I'm sure we'll be seeing more GPU accelerated effects.

 

[Eggz]

I did just read that Unreal Engine 4 is incorporating the latest PhysX version, so I'm sure we'll be seeing more GPU accelerated effects.

I really hope so. This CPU business is ridiculous!

 

[Andy Weller]

i wonder how many people spent good money on buying a second card just so they could experience the best of Physx in this game?

I also wonder if this is why the game was delayed 3 months?!

 

[renz496]

Doubt that it was just because of PhysX. PhysX has been the core physic engine for Red Engine 3. So physx has been there since the very beginning. And we know about stuff like hairworks since early developement it witcher 3 as well. Most likely they delay the game to polish the game further seing how big the game world are.

 

[Eggz]

The performance with PhysX was bad enough for me to just return the game. Over it